From 289e6efe62e90bce253131db34f5126dd7a0ec23 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 12:07:29 -0400
Subject: [PATCH 01/31] feat(test): test panel

---
 lua/cp/config.lua      |  63 ++++++++++++++++
 lua/cp/diff.lua        | 150 +++++++++++++++++++++++++++++++++++++
 lua/cp/highlight.lua   | 164 +++++++++++++++++++++++++++++++++++++++++
 lua/cp/init.lua        |  90 +++++++---------------
 lua/cp/test_render.lua | 102 +++++++++++++++++++++++++
 5 files changed, 504 insertions(+), 65 deletions(-)
 create mode 100644 lua/cp/diff.lua
 create mode 100644 lua/cp/highlight.lua
 create mode 100644 lua/cp/test_render.lua

diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index cae943a..a36f6f2 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -31,6 +31,22 @@
 ---@field before_debug? fun(ctx: ProblemContext)
 ---@field setup_code? fun(ctx: ProblemContext)
 
+---@class TestPanelConfig
+---@field diff_mode "vim"|"git" Diff backend to use
+---@field toggle_key string Key to toggle test panel
+---@field status_format "compact"|"verbose" Status display format
+
+---@class DiffGitConfig
+---@field command string Git executable name
+---@field args string[] Additional git diff arguments
+
+---@class DiffVimConfig
+---@field enable_diffthis boolean Enable vim's diffthis
+
+---@class DiffConfig
+---@field git DiffGitConfig
+---@field vim DiffVimConfig
+
 ---@class cp.Config
 ---@field contests table<string, ContestConfig>
 ---@field snippets table[]
@@ -38,6 +54,8 @@
 ---@field debug boolean
 ---@field scrapers table<string, boolean>
 ---@field filename? fun(contest: string, contest_id: string, problem_id?: string, config: cp.Config, language?: string): string
+---@field test_panel TestPanelConfig
+---@field diff DiffConfig
 
 ---@class cp.UserConfig
 ---@field contests? table<string, PartialContestConfig>
@@ -46,6 +64,8 @@
 ---@field debug? boolean
 ---@field scrapers? table<string, boolean>
 ---@field filename? fun(contest: string, contest_id: string, problem_id?: string, config: cp.Config, language?: string): string
+---@field test_panel? TestPanelConfig
+---@field diff? DiffConfig
 
 local M = {}
 local constants = require('cp.constants')
@@ -62,6 +82,20 @@ M.defaults = {
   debug = false,
   scrapers = constants.PLATFORMS,
   filename = nil,
+  test_panel = {
+    diff_mode = "vim",
+    toggle_key = "t",
+    status_format = "compact",
+  },
+  diff = {
+    git = {
+      command = "git",
+      args = {"diff", "--no-index", "--word-diff=plain", "--word-diff-regex=.", "--no-prefix"},
+    },
+    vim = {
+      enable_diffthis = true,
+    },
+  },
 }
 
 ---@param user_config cp.UserConfig|nil
@@ -79,6 +113,8 @@ function M.setup(user_config)
       debug = { user_config.debug, { 'boolean', 'nil' }, true },
       scrapers = { user_config.scrapers, { 'table', 'nil' }, true },
       filename = { user_config.filename, { 'function', 'nil' }, true },
+      test_panel = { user_config.test_panel, { 'table', 'nil' }, true },
+      diff = { user_config.diff, { 'table', 'nil' }, true },
     })
 
     if user_config.hooks then
@@ -101,6 +137,33 @@ function M.setup(user_config)
       })
     end
 
+    if user_config.test_panel then
+      vim.validate({
+        diff_mode = {
+          user_config.test_panel.diff_mode,
+          function(value)
+            return vim.tbl_contains({"vim", "git"}, value)
+          end,
+          "diff_mode must be 'vim' or 'git'",
+        },
+        toggle_key = { user_config.test_panel.toggle_key, 'string', true },
+        status_format = {
+          user_config.test_panel.status_format,
+          function(value)
+            return vim.tbl_contains({"compact", "verbose"}, value)
+          end,
+          "status_format must be 'compact' or 'verbose'",
+        },
+      })
+    end
+
+    if user_config.diff then
+      vim.validate({
+        git = { user_config.diff.git, { 'table', 'nil' }, true },
+        vim = { user_config.diff.vim, { 'table', 'nil' }, true },
+      })
+    end
+
     if user_config.contests then
       for contest_name, contest_config in pairs(user_config.contests) do
         for lang_name, lang_config in pairs(contest_config) do
diff --git a/lua/cp/diff.lua b/lua/cp/diff.lua
new file mode 100644
index 0000000..03928fa
--- /dev/null
+++ b/lua/cp/diff.lua
@@ -0,0 +1,150 @@
+---@class DiffResult
+---@field content string[]
+---@field highlights table[]?
+
+---@class DiffBackend
+---@field name string
+---@field render fun(expected: string, actual: string, mode: string?): DiffResult
+
+local M = {}
+
+---Vim's built-in diff backend using diffthis
+---@type DiffBackend
+local vim_backend = {
+  name = 'vim',
+  render = function(expected, actual, mode)
+    -- For vim backend, we return the content as-is since diffthis handles highlighting
+    local expected_lines = vim.split(expected, '\n', { plain = true, trimempty = true })
+    local actual_lines = vim.split(actual, '\n', { plain = true, trimempty = true })
+
+    return {
+      content = actual_lines,
+      highlights = nil -- diffthis handles highlighting
+    }
+  end
+}
+
+---Git word-diff backend for character-level precision
+---@type DiffBackend
+local git_backend = {
+  name = 'git',
+  render = function(expected, actual, mode)
+    -- Create temporary files for git diff
+    local tmp_expected = vim.fn.tempname()
+    local tmp_actual = vim.fn.tempname()
+
+    vim.fn.writefile(vim.split(expected, '\n', { plain = true }), tmp_expected)
+    vim.fn.writefile(vim.split(actual, '\n', { plain = true }), tmp_actual)
+
+    local cmd = {
+      'git', 'diff', '--no-index', '--word-diff=plain', '--word-diff-regex=.',
+      '--no-prefix', tmp_expected, tmp_actual
+    }
+
+    local result = vim.system(cmd, { text = true }):wait()
+
+    -- Clean up temp files
+    vim.fn.delete(tmp_expected)
+    vim.fn.delete(tmp_actual)
+
+    if result.code == 0 then
+      -- No differences, return actual content as-is
+      return {
+        content = vim.split(actual, '\n', { plain = true, trimempty = true }),
+        highlights = {}
+      }
+    else
+      -- Parse git diff output
+      local lines = vim.split(result.stdout or '', '\n', { plain = true })
+      local content_lines = {}
+      local highlights = {}
+
+      -- Skip git diff header lines (start with @@, +++, ---, etc.)
+      local content_started = false
+      for _, line in ipairs(lines) do
+        if content_started or (not line:match('^@@') and not line:match('^%+%+%+') and not line:match('^%-%-%-') and not line:match('^index')) then
+          content_started = true
+          if line:match('^[^%-+]') or line:match('^%+') then
+            -- Skip lines starting with - (removed lines) for the actual pane
+            -- Only show lines that are unchanged or added
+            if not line:match('^%-') then
+              local clean_line = line:gsub('^%+', '') -- Remove + prefix
+              table.insert(content_lines, clean_line)
+
+              -- Parse highlights will be handled in highlight.lua
+              table.insert(highlights, {
+                line = #content_lines,
+                content = clean_line
+              })
+            end
+          end
+        end
+      end
+
+      return {
+        content = content_lines,
+        highlights = highlights
+      }
+    end
+  end
+}
+
+---Available diff backends
+---@type table<string, DiffBackend>
+local backends = {
+  vim = vim_backend,
+  git = git_backend,
+}
+
+---Get available backend names
+---@return string[]
+function M.get_available_backends()
+  return vim.tbl_keys(backends)
+end
+
+---Get a diff backend by name
+---@param name string
+---@return DiffBackend?
+function M.get_backend(name)
+  return backends[name]
+end
+
+---Check if git backend is available
+---@return boolean
+function M.is_git_available()
+  local result = vim.system({'git', '--version'}, { text = true }):wait()
+  return result.code == 0
+end
+
+---Get the best available backend based on config and system availability
+---@param preferred_backend? string
+---@return DiffBackend
+function M.get_best_backend(preferred_backend)
+  if preferred_backend and backends[preferred_backend] then
+    if preferred_backend == 'git' and not M.is_git_available() then
+      -- Fall back to vim if git is not available
+      return backends.vim
+    end
+    return backends[preferred_backend]
+  end
+
+  -- Default to git if available, otherwise vim
+  if M.is_git_available() then
+    return backends.git
+  else
+    return backends.vim
+  end
+end
+
+---Render diff using specified backend
+---@param expected string
+---@param actual string
+---@param backend_name? string
+---@param mode? string
+---@return DiffResult
+function M.render_diff(expected, actual, backend_name, mode)
+  local backend = M.get_best_backend(backend_name)
+  return backend.render(expected, actual, mode)
+end
+
+return M
\ No newline at end of file
diff --git a/lua/cp/highlight.lua b/lua/cp/highlight.lua
new file mode 100644
index 0000000..13d7e65
--- /dev/null
+++ b/lua/cp/highlight.lua
@@ -0,0 +1,164 @@
+---@class DiffHighlight
+---@field line number
+---@field col_start number
+---@field col_end number
+---@field highlight_group string
+
+---@class ParsedDiff
+---@field content string[]
+---@field highlights DiffHighlight[]
+
+local M = {}
+
+---Parse git diff markers and extract highlight information
+---@param text string Raw git diff output line
+---@return string cleaned_text, DiffHighlight[]
+local function parse_diff_line(text)
+  local highlights = {}
+  local cleaned_text = text
+  local offset = 0
+
+  -- Pattern for removed text: [-removed text-]
+  for removed_text in text:gmatch('%[%-(.-)%-%]') do
+    local start_pos = text:find('%[%-' .. vim.pesc(removed_text) .. '%-%]', 1, false)
+    if start_pos then
+      -- Remove the marker and adjust positions
+      local marker_len = #('[-%-%]') + #removed_text
+      cleaned_text = cleaned_text:gsub('%[%-' .. vim.pesc(removed_text) .. '%-%]', '', 1)
+
+      -- Since we're removing text, we don't add highlights for removed content in the actual pane
+      -- This is handled by showing removed content in the expected pane
+    end
+  end
+
+  -- Reset for added text parsing on the cleaned text
+  local final_text = cleaned_text
+  local final_highlights = {}
+  offset = 0
+
+  -- Pattern for added text: {+added text+}
+  for added_text in cleaned_text:gmatch('{%+(.-)%+}') do
+    local start_pos = final_text:find('{%+' .. vim.pesc(added_text) .. '%+}', 1, false)
+    if start_pos then
+      -- Calculate position after previous highlights
+      local highlight_start = start_pos - offset - 1  -- 0-based for extmarks
+      local highlight_end = highlight_start + #added_text
+
+      table.insert(final_highlights, {
+        line = 0, -- Will be set by caller
+        col_start = highlight_start,
+        col_end = highlight_end,
+        highlight_group = 'CpDiffAdded'
+      })
+
+      -- Remove the marker
+      local marker_len = #{'{+'} + #{'+}'} + #added_text
+      final_text = final_text:gsub('{%+' .. vim.pesc(added_text) .. '%+}', added_text, 1)
+      offset = offset + #{'{+'} + #{'+}'}
+    end
+  end
+
+  return final_text, final_highlights
+end
+
+---Parse complete git diff output
+---@param diff_output string
+---@return ParsedDiff
+function M.parse_git_diff(diff_output)
+  local lines = vim.split(diff_output, '\n', { plain = true })
+  local content_lines = {}
+  local all_highlights = {}
+
+  -- Skip git diff header lines
+  local content_started = false
+  for _, line in ipairs(lines) do
+    -- Skip header lines (@@, +++, ---, index, etc.)
+    if content_started or (
+      not line:match('^@@') and
+      not line:match('^%+%+%+') and
+      not line:match('^%-%-%-') and
+      not line:match('^index') and
+      not line:match('^diff %-%-git')
+    ) then
+      content_started = true
+
+      -- Process content lines
+      if line:match('^%+') then
+        -- Added line - remove + prefix and parse highlights
+        local clean_line = line:sub(2) -- Remove + prefix
+        local parsed_line, line_highlights = parse_diff_line(clean_line)
+
+        table.insert(content_lines, parsed_line)
+
+        -- Set line numbers for highlights
+        local line_num = #content_lines
+        for _, highlight in ipairs(line_highlights) do
+          highlight.line = line_num - 1 -- 0-based for extmarks
+          table.insert(all_highlights, highlight)
+        end
+      elseif line:match('^%-') then
+        -- Removed line - we handle this in the expected pane, skip for actual
+      elseif not line:match('^\\') then -- Skip "\ No newline" messages
+        -- Unchanged line
+        local parsed_line, line_highlights = parse_diff_line(line)
+        table.insert(content_lines, parsed_line)
+
+        -- Set line numbers for any highlights (shouldn't be any for unchanged lines)
+        local line_num = #content_lines
+        for _, highlight in ipairs(line_highlights) do
+          highlight.line = line_num - 1 -- 0-based for extmarks
+          table.insert(all_highlights, highlight)
+        end
+      end
+    end
+  end
+
+  return {
+    content = content_lines,
+    highlights = all_highlights
+  }
+end
+
+---Apply highlights to a buffer using extmarks
+---@param bufnr number
+---@param highlights DiffHighlight[]
+---@param namespace number
+function M.apply_highlights(bufnr, highlights, namespace)
+  -- Clear existing highlights in this namespace
+  vim.api.nvim_buf_clear_namespace(bufnr, namespace, 0, -1)
+
+  for _, highlight in ipairs(highlights) do
+    if highlight.col_start < highlight.col_end then
+      vim.api.nvim_buf_set_extmark(bufnr, namespace, highlight.line, highlight.col_start, {
+        end_col = highlight.col_end,
+        hl_group = highlight.highlight_group,
+        priority = 100,
+      })
+    end
+  end
+end
+
+---Create namespace for diff highlights
+---@return number
+function M.create_namespace()
+  return vim.api.nvim_create_namespace('cp_diff_highlights')
+end
+
+---Parse and apply git diff to buffer
+---@param bufnr number
+---@param diff_output string
+---@param namespace number
+---@return string[] content_lines
+function M.parse_and_apply_diff(bufnr, diff_output, namespace)
+  local parsed = M.parse_git_diff(diff_output)
+
+  -- Set buffer content
+  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, parsed.content)
+
+  -- Apply highlights
+  M.apply_highlights(bufnr, parsed.highlights, namespace)
+
+  return parsed.content
+end
+
+return M
\ No newline at end of file
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 075ee65..607b8ad 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -191,9 +191,13 @@ local function toggle_test_panel(is_debug)
   local expected_buf = vim.api.nvim_create_buf(false, true)
   local actual_buf = vim.api.nvim_create_buf(false, true)
 
-  vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = tab_buf })
-  vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = expected_buf })
-  vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = actual_buf })
+  -- Set buffer options
+  local buffer_opts = { 'bufhidden', 'wipe' }
+  for _, buf in ipairs({tab_buf, expected_buf, actual_buf}) do
+    vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
+    vim.api.nvim_set_option_value('readonly', true, { buf = buf })
+    vim.api.nvim_set_option_value('modifiable', false, { buf = buf })
+  end
 
   local main_win = vim.api.nvim_get_current_win()
   vim.api.nvim_win_set_buf(main_win, tab_buf)
@@ -222,61 +226,16 @@ local function toggle_test_panel(is_debug)
   }
 
   local function render_test_tabs()
+    local test_render = require('cp.test_render')
+    test_render.setup_highlights()
     local test_state = test_module.get_test_panel_state()
-    local tab_lines = {}
+    return test_render.render_test_list(test_state, config.test_panel)
+  end
 
-    local max_status_width = 0
-    local max_code_width = 0
-    local max_time_width = 0
-
-    for _, test_case in ipairs(test_state.test_cases) do
-      local status_text = test_case.status == 'pending' and '' or string.upper(test_case.status)
-      max_status_width = math.max(max_status_width, #status_text)
-
-      if test_case.code then
-        max_code_width = math.max(max_code_width, #tostring(test_case.code))
-      end
-
-      if test_case.time_ms then
-        local time_text = string.format('%.0fms', test_case.time_ms)
-        max_time_width = math.max(max_time_width, #time_text)
-      end
-    end
-
-    for i, test_case in ipairs(test_state.test_cases) do
-      local prefix = i == test_state.current_index and '> ' or '  '
-      local tab = string.format('%s%d.', prefix, i)
-
-      if test_case.ok ~= nil then
-        tab = tab .. string.format(' [ok:%-5s]', tostring(test_case.ok))
-      end
-
-      if test_case.code then
-        tab = tab .. string.format(' [code:%-' .. max_code_width .. 's]', tostring(test_case.code))
-      end
-
-      if test_case.time_ms then
-        local time_text = string.format('%.0fms', test_case.time_ms)
-        tab = tab .. string.format(' [time:%-' .. max_time_width .. 's]', time_text)
-      end
-
-      if test_case.signal then
-        tab = tab .. string.format(' [%s]', test_case.signal)
-      end
-
-      table.insert(tab_lines, tab)
-    end
-
-    local current_test = test_state.test_cases[test_state.current_index]
-    if current_test then
-      table.insert(tab_lines, '')
-      table.insert(tab_lines, 'Input:')
-      for _, line in ipairs(vim.split(current_test.input, '\n', { plain = true, trimempty = true })) do
-        table.insert(tab_lines, line)
-      end
-    end
-
-    return tab_lines
+  local function update_buffer_content(bufnr, lines)
+    vim.api.nvim_set_option_value('modifiable', true, { buf = bufnr })
+    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
+    vim.api.nvim_set_option_value('modifiable', false, { buf = bufnr })
   end
 
   local function update_expected_pane()
@@ -290,11 +249,7 @@ local function toggle_test_panel(is_debug)
     local expected_text = current_test.expected
     local expected_lines = vim.split(expected_text, '\n', { plain = true, trimempty = true })
 
-    vim.api.nvim_buf_set_lines(test_buffers.expected_buf, 0, -1, false, expected_lines)
-
-    if vim.fn.has('nvim-0.8.0') == 1 then
-      vim.api.nvim_set_option_value('winbar', 'Expected', { win = test_windows.expected_win })
-    end
+    update_buffer_content(test_buffers.expected_buf, expected_lines)
   end
 
   local function update_actual_pane()
@@ -315,10 +270,12 @@ local function toggle_test_panel(is_debug)
       actual_lines = { '(not run yet)' }
     end
 
-    vim.api.nvim_buf_set_lines(test_buffers.actual_buf, 0, -1, false, actual_lines)
+    update_buffer_content(test_buffers.actual_buf, actual_lines)
 
-    if vim.fn.has('nvim-0.8.0') == 1 then
-      vim.api.nvim_set_option_value('winbar', 'Actual', { win = test_windows.actual_win })
+    local test_render = require('cp.test_render')
+    local status_bar_text = test_render.render_status_bar(current_test)
+    if status_bar_text ~= '' then
+      vim.api.nvim_set_option_value('winbar', status_bar_text, { win = test_windows.actual_win })
     end
 
     vim.api.nvim_set_option_value('diff', enable_diff, { win = test_windows.expected_win })
@@ -340,7 +297,7 @@ local function toggle_test_panel(is_debug)
     end
 
     local tab_lines = render_test_tabs()
-    vim.api.nvim_buf_set_lines(test_buffers.tab_buf, 0, -1, false, tab_lines)
+    update_buffer_content(test_buffers.tab_buf, tab_lines)
 
     update_expected_pane()
     update_actual_pane()
@@ -373,6 +330,9 @@ local function toggle_test_panel(is_debug)
     vim.keymap.set('n', 'q', function()
       toggle_test_panel()
     end, { buffer = buf, silent = true })
+    vim.keymap.set('n', config.test_panel.toggle_key, function()
+      toggle_test_panel()
+    end, { buffer = buf, silent = true })
   end
 
   if is_debug and config.hooks and config.hooks.before_debug then
diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
new file mode 100644
index 0000000..5ca1298
--- /dev/null
+++ b/lua/cp/test_render.lua
@@ -0,0 +1,102 @@
+---@class TestRenderConfig
+---@field status_format "compact"|"verbose"
+
+---@class StatusInfo
+---@field text string
+---@field highlight_group string
+
+local M = {}
+
+---Convert test status to CP terminology with colors
+---@param test_case TestCase
+---@return StatusInfo
+local function get_status_info(test_case)
+  if test_case.status == 'pass' then
+    return { text = 'AC', highlight_group = 'CpTestAC' }
+  elseif test_case.status == 'fail' then
+    if test_case.timed_out then
+      return { text = 'TLE', highlight_group = 'CpTestError' }
+    elseif test_case.code and test_case.code ~= 0 then
+      return { text = 'RTE', highlight_group = 'CpTestError' }
+    else
+      return { text = 'WA', highlight_group = 'CpTestError' }
+    end
+  elseif test_case.status == 'timeout' then
+    return { text = 'TLE', highlight_group = 'CpTestError' }
+  elseif test_case.status == 'running' then
+    return { text = '...', highlight_group = 'CpTestPending' }
+  else
+    return { text = '', highlight_group = 'CpTestPending' }
+  end
+end
+
+---Render test cases list with improved layout
+---@param test_state TestPanelState
+---@param config? TestRenderConfig
+---@return string[]
+function M.render_test_list(test_state, config)
+  config = config or { status_format = 'compact' }
+  local lines = {}
+
+  for i, test_case in ipairs(test_state.test_cases) do
+    local is_current = i == test_state.current_index
+    local prefix = is_current and '> ' or '  '
+    local status_info = get_status_info(test_case)
+
+    local status_text = status_info.text ~= '' and status_info.text or ''
+    local line = string.format('%s%d. %s', prefix, i, status_text)
+
+    table.insert(lines, line)
+
+    if is_current and test_case.input and test_case.input ~= '' then
+      for _, input_line in ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false })) do
+        table.insert(lines, '  ' .. input_line)
+      end
+    end
+  end
+
+  return lines
+end
+
+---Create status bar content for diff pane
+---@param test_case TestCase?
+---@return string
+function M.render_status_bar(test_case)
+  if not test_case then
+    return ''
+  end
+
+  local parts = {}
+
+  if test_case.time_ms then
+    table.insert(parts, string.format('%.0fms', test_case.time_ms))
+  end
+
+  if test_case.code then
+    table.insert(parts, string.format('Exit: %d', test_case.code))
+  end
+
+  return table.concat(parts, ' │ ')
+end
+
+---Get highlight groups needed for test rendering
+---@return table<string, table>
+function M.get_highlight_groups()
+  return {
+    CpTestAC = { fg = '#10b981', bold = true },
+    CpTestError = { fg = '#ef4444', bold = true },
+    CpTestPending = { fg = '#6b7280' },
+    CpDiffRemoved = { fg = '#ef4444', bg = '#1f1f1f' },
+    CpDiffAdded = { fg = '#10b981', bg = '#1f1f1f' },
+  }
+end
+
+---Setup highlight groups
+function M.setup_highlights()
+  local groups = M.get_highlight_groups()
+  for group_name, opts in pairs(groups) do
+    vim.api.nvim_set_hl(0, group_name, opts)
+  end
+end
+
+return M

From d193fabfb9fc34e6c1a4616fcb1755ebc7e5b923 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 12:11:50 -0400
Subject: [PATCH 02/31] feat(test: git diff backend

---
 doc/cp.txt      | 87 ++++++++++++++++++++++++++++++++++++++-----------
 lua/cp/diff.lua | 42 +++---------------------
 lua/cp/init.lua | 48 ++++++++++++++++++++-------
 3 files changed, 110 insertions(+), 67 deletions(-)

diff --git a/doc/cp.txt b/doc/cp.txt
index f743f51..4e8f3ac 100644
--- a/doc/cp.txt
+++ b/doc/cp.txt
@@ -50,8 +50,8 @@ Setup Commands ~
 Action Commands ~
 
 :CP test [--debug]              Toggle test panel for individual test case
-                                debugging. Shows per-test results with three-pane
-                                layout for easy Expected/Actual comparison.
+                                debugging. Shows per-test results with redesigned
+                                layout for efficient comparison.
                                 Use --debug flag to compile with debug flags
                                 Requires contest setup first.
 
@@ -115,6 +115,21 @@ Optional configuration with lazy.nvim: >
               vim.diagnostic.enable(false)
             end,
           },
+          test_panel = {
+            diff_mode = "vim",        -- "vim" or "git"
+            toggle_key = "t",         -- key to toggle test panel
+            status_format = "compact", -- "compact" or "verbose"
+          },
+          diff = {
+            git = {
+              command = "git",
+              args = {"diff", "--no-index", "--word-diff=plain",
+                     "--word-diff-regex=.", "--no-prefix"},
+            },
+            vim = {
+              enable_diffthis = true,
+            },
+          },
           snippets = { ... },  -- LuaSnip snippets
           filename = function(contest, contest_id, problem_id, config, language) ... end,
         }
@@ -131,6 +146,8 @@ Optional configuration with lazy.nvim: >
                         during operation.
       • {scrapers}      (`table<string,boolean>`) Per-platform scraper control.
                          Default enables all platforms.
+      • {test_panel}    (`TestPanelConfig`) Test panel behavior configuration.
+      • {diff}          (`DiffConfig`) Diff backend configuration.
       • {filename}?     (`function`) Custom filename generation function.
                         `function(contest, contest_id, problem_id, config, language)`
                         Should return full filename with extension.
@@ -157,6 +174,20 @@ Optional configuration with lazy.nvim: >
       • {extension}     (`string`) File extension (e.g. "cc", "py").
       • {executable}?   (`string`) Executable name for interpreted languages.
 
+*cp.TestPanelConfig*
+
+    Fields: ~
+      • {diff_mode}     (`string`, default: `"vim"`) Diff backend: "vim" or "git".
+                        Git provides character-level precision, vim uses built-in diff.
+      • {toggle_key}    (`string`, default: `"t"`) Key to toggle test panel.
+      • {status_format} (`string`, default: `"compact"`) Status display format.
+
+*cp.DiffConfig*
+
+    Fields: ~
+      • {git}           (`DiffGitConfig`) Git diff backend configuration.
+      • {vim}           (`DiffVimConfig`) Vim diff backend configuration.
+
 *cp.Hooks*
 
     Fields: ~
@@ -256,8 +287,9 @@ Example: Quick setup for single Codeforces problem >
 
 TEST PANEL                                          *cp-test*
 
-The test panel provides individual test case debugging with a three-pane
-layout showing test list, expected output, and actual output side-by-side.
+The test panel provides individual test case debugging with a streamlined
+layout optimized for modern screens. Shows test status with competitive
+programming terminology and efficient space usage.
 
 Activation ~
                                                       *:CP-test*
@@ -270,29 +302,46 @@ Activation ~
 
 Interface ~
 
-The test panel uses a three-pane layout for easy comparison: >
+The test panel uses a redesigned two-pane layout for efficient comparison:
+(note that the diff is indeed highlighted, not the weird amalgamation of
+characters below) >
 
-    ┌─────────────────────────────────────────────────────────────┐
-    │  1. [ok:true ] [code:0] [time:12ms]                         │
-    │> 2. [ok:false] [code:0] [time:45ms]                         │
-    │                                                             │
-    │ Input:                                                      │
-    │ 5 3                                                         │
-    │                                                             │
-    └─────────────────────────────────────────────────────────────┘
-    ┌─ Expected ──────────────────┐ ┌───── Actual ────────────────┐
-    │ 8                           │ │ 7                           │
-    │                             │ │                             │
-    │                             │ │                             │
-    │                             │ │                             │
-    └─────────────────────────────┘ └─────────────────────────────┘
+    ┌─ Tests ─────────────────────┐ ┌─ Expected vs Actual ───────────────────────┐
+    │ AC  1. 12ms                 │ │                             45ms │ Exit: 0 │
+    │ WA  > 2. 45ms               │ ├────────────────────────────────────────────┤
+    │     5 3                     │ │                                            │
+    │                             │ │ 4[-2-]{+3+}                                │
+    │ AC  3. 9ms                  │ │ 100                                        │
+    │ RTE 4. 0ms                  │ │ hello w[-o-]r{+o+}ld                       │
+    │                             │ │                                            │
+    └─────────────────────────────┘ └────────────────────────────────────────────┘
 <
 
+Status Indicators ~
+
+Test cases use competitive programming terminology:
+
+    AC      Accepted (passed)
+    WA      Wrong Answer (output mismatch)
+    TLE     Time Limit Exceeded (timeout)
+    RTE     Runtime Error (non-zero exit)
+
 Keymaps ~
                                                 *cp-test-keys*
 <c-n>                           Navigate to next test case
 <c-p>                           Navigate to previous test case
 q                               Exit test panel (restore layout)
+t                               Toggle test panel (configurable via test_panel.toggle_key)
+
+Diff Modes ~
+
+Two diff backends are available:
+
+    vim     Built-in vim diff (default, always available)
+    git     Character-level git word-diff (requires git, more precise)
+
+The git backend shows character-level changes with [-removed-] and {+added+}
+markers for precise difference analysis.
 
 Execution Details ~
 
diff --git a/lua/cp/diff.lua b/lua/cp/diff.lua
index 03928fa..97c1b76 100644
--- a/lua/cp/diff.lua
+++ b/lua/cp/diff.lua
@@ -48,42 +48,16 @@ local git_backend = {
     vim.fn.delete(tmp_actual)
 
     if result.code == 0 then
-      -- No differences, return actual content as-is
       return {
         content = vim.split(actual, '\n', { plain = true, trimempty = true }),
         highlights = {}
       }
     else
-      -- Parse git diff output
-      local lines = vim.split(result.stdout or '', '\n', { plain = true })
-      local content_lines = {}
-      local highlights = {}
-
-      -- Skip git diff header lines (start with @@, +++, ---, etc.)
-      local content_started = false
-      for _, line in ipairs(lines) do
-        if content_started or (not line:match('^@@') and not line:match('^%+%+%+') and not line:match('^%-%-%-') and not line:match('^index')) then
-          content_started = true
-          if line:match('^[^%-+]') or line:match('^%+') then
-            -- Skip lines starting with - (removed lines) for the actual pane
-            -- Only show lines that are unchanged or added
-            if not line:match('^%-') then
-              local clean_line = line:gsub('^%+', '') -- Remove + prefix
-              table.insert(content_lines, clean_line)
-
-              -- Parse highlights will be handled in highlight.lua
-              table.insert(highlights, {
-                line = #content_lines,
-                content = clean_line
-              })
-            end
-          end
-        end
-      end
-
+      local highlight_module = require('cp.highlight')
       return {
-        content = content_lines,
-        highlights = highlights
+        content = {},
+        highlights = {},
+        raw_diff = result.stdout or ''
       }
     end
   end
@@ -122,18 +96,12 @@ end
 function M.get_best_backend(preferred_backend)
   if preferred_backend and backends[preferred_backend] then
     if preferred_backend == 'git' and not M.is_git_available() then
-      -- Fall back to vim if git is not available
       return backends.vim
     end
     return backends[preferred_backend]
   end
 
-  -- Default to git if available, otherwise vim
-  if M.is_git_available() then
-    return backends.git
-  else
-    return backends.vim
-  end
+  return backends.vim
 end
 
 ---Render diff using specified backend
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 607b8ad..c16f185 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -225,6 +225,9 @@ local function toggle_test_panel(is_debug)
     actual_buf = actual_buf,
   }
 
+  local highlight = require('cp.highlight')
+  local diff_namespace = highlight.create_namespace()
+
   local function render_test_tabs()
     local test_render = require('cp.test_render')
     test_render.setup_highlights()
@@ -250,6 +253,15 @@ local function toggle_test_panel(is_debug)
     local expected_lines = vim.split(expected_text, '\n', { plain = true, trimempty = true })
 
     update_buffer_content(test_buffers.expected_buf, expected_lines)
+
+    local diff_backend = require('cp.diff')
+    local backend = diff_backend.get_best_backend(config.test_panel.diff_mode)
+
+    if backend.name == 'vim' and current_test.status == 'fail' then
+      vim.api.nvim_set_option_value('diff', true, { win = test_windows.expected_win })
+    else
+      vim.api.nvim_set_option_value('diff', false, { win = test_windows.expected_win })
+    end
   end
 
   local function update_actual_pane()
@@ -270,24 +282,38 @@ local function toggle_test_panel(is_debug)
       actual_lines = { '(not run yet)' }
     end
 
-    update_buffer_content(test_buffers.actual_buf, actual_lines)
-
     local test_render = require('cp.test_render')
     local status_bar_text = test_render.render_status_bar(current_test)
     if status_bar_text ~= '' then
       vim.api.nvim_set_option_value('winbar', status_bar_text, { win = test_windows.actual_win })
     end
 
-    vim.api.nvim_set_option_value('diff', enable_diff, { win = test_windows.expected_win })
-    vim.api.nvim_set_option_value('diff', enable_diff, { win = test_windows.actual_win })
-
     if enable_diff then
-      vim.api.nvim_win_call(test_windows.expected_win, function()
-        vim.cmd.diffthis()
-      end)
-      vim.api.nvim_win_call(test_windows.actual_win, function()
-        vim.cmd.diffthis()
-      end)
+      local diff_backend = require('cp.diff')
+      local backend = diff_backend.get_best_backend(config.test_panel.diff_mode)
+
+      if backend.name == 'git' then
+        local diff_result = backend.render(current_test.expected, current_test.actual)
+        if diff_result.raw_diff and diff_result.raw_diff ~= '' then
+          highlight.parse_and_apply_diff(test_buffers.actual_buf, diff_result.raw_diff, diff_namespace)
+        else
+          update_buffer_content(test_buffers.actual_buf, actual_lines)
+        end
+      else
+        update_buffer_content(test_buffers.actual_buf, actual_lines)
+        vim.api.nvim_set_option_value('diff', true, { win = test_windows.expected_win })
+        vim.api.nvim_set_option_value('diff', true, { win = test_windows.actual_win })
+        vim.api.nvim_win_call(test_windows.expected_win, function()
+          vim.cmd.diffthis()
+        end)
+        vim.api.nvim_win_call(test_windows.actual_win, function()
+          vim.cmd.diffthis()
+        end)
+      end
+    else
+      update_buffer_content(test_buffers.actual_buf, actual_lines)
+      vim.api.nvim_set_option_value('diff', false, { win = test_windows.expected_win })
+      vim.api.nvim_set_option_value('diff', false, { win = test_windows.actual_win })
     end
   end
 

From ab9a0f43b53ae787856605c8b2ea6473fef3a52e Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 12:11:56 -0400
Subject: [PATCH 03/31] fix(ci): format

---
 lua/cp/config.lua      | 14 +++++++-------
 lua/cp/diff.lua        | 24 +++++++++++++++---------
 lua/cp/highlight.lua   | 31 +++++++++++++++++--------------
 lua/cp/init.lua        |  8 ++++++--
 lua/cp/test_render.lua |  4 +++-
 5 files changed, 48 insertions(+), 33 deletions(-)

diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index a36f6f2..ca82b99 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -83,14 +83,14 @@ M.defaults = {
   scrapers = constants.PLATFORMS,
   filename = nil,
   test_panel = {
-    diff_mode = "vim",
-    toggle_key = "t",
-    status_format = "compact",
+    diff_mode = 'vim',
+    toggle_key = 't',
+    status_format = 'compact',
   },
   diff = {
     git = {
-      command = "git",
-      args = {"diff", "--no-index", "--word-diff=plain", "--word-diff-regex=.", "--no-prefix"},
+      command = 'git',
+      args = { 'diff', '--no-index', '--word-diff=plain', '--word-diff-regex=.', '--no-prefix' },
     },
     vim = {
       enable_diffthis = true,
@@ -142,7 +142,7 @@ function M.setup(user_config)
         diff_mode = {
           user_config.test_panel.diff_mode,
           function(value)
-            return vim.tbl_contains({"vim", "git"}, value)
+            return vim.tbl_contains({ 'vim', 'git' }, value)
           end,
           "diff_mode must be 'vim' or 'git'",
         },
@@ -150,7 +150,7 @@ function M.setup(user_config)
         status_format = {
           user_config.test_panel.status_format,
           function(value)
-            return vim.tbl_contains({"compact", "verbose"}, value)
+            return vim.tbl_contains({ 'compact', 'verbose' }, value)
           end,
           "status_format must be 'compact' or 'verbose'",
         },
diff --git a/lua/cp/diff.lua b/lua/cp/diff.lua
index 97c1b76..c665b78 100644
--- a/lua/cp/diff.lua
+++ b/lua/cp/diff.lua
@@ -19,9 +19,9 @@ local vim_backend = {
 
     return {
       content = actual_lines,
-      highlights = nil -- diffthis handles highlighting
+      highlights = nil, -- diffthis handles highlighting
     }
-  end
+  end,
 }
 
 ---Git word-diff backend for character-level precision
@@ -37,8 +37,14 @@ local git_backend = {
     vim.fn.writefile(vim.split(actual, '\n', { plain = true }), tmp_actual)
 
     local cmd = {
-      'git', 'diff', '--no-index', '--word-diff=plain', '--word-diff-regex=.',
-      '--no-prefix', tmp_expected, tmp_actual
+      'git',
+      'diff',
+      '--no-index',
+      '--word-diff=plain',
+      '--word-diff-regex=.',
+      '--no-prefix',
+      tmp_expected,
+      tmp_actual,
     }
 
     local result = vim.system(cmd, { text = true }):wait()
@@ -50,17 +56,17 @@ local git_backend = {
     if result.code == 0 then
       return {
         content = vim.split(actual, '\n', { plain = true, trimempty = true }),
-        highlights = {}
+        highlights = {},
       }
     else
       local highlight_module = require('cp.highlight')
       return {
         content = {},
         highlights = {},
-        raw_diff = result.stdout or ''
+        raw_diff = result.stdout or '',
       }
     end
-  end
+  end,
 }
 
 ---Available diff backends
@@ -86,7 +92,7 @@ end
 ---Check if git backend is available
 ---@return boolean
 function M.is_git_available()
-  local result = vim.system({'git', '--version'}, { text = true }):wait()
+  local result = vim.system({ 'git', '--version' }, { text = true }):wait()
   return result.code == 0
 end
 
@@ -115,4 +121,4 @@ function M.render_diff(expected, actual, backend_name, mode)
   return backend.render(expected, actual, mode)
 end
 
-return M
\ No newline at end of file
+return M
diff --git a/lua/cp/highlight.lua b/lua/cp/highlight.lua
index 13d7e65..3145a15 100644
--- a/lua/cp/highlight.lua
+++ b/lua/cp/highlight.lua
@@ -23,7 +23,7 @@ local function parse_diff_line(text)
     local start_pos = text:find('%[%-' .. vim.pesc(removed_text) .. '%-%]', 1, false)
     if start_pos then
       -- Remove the marker and adjust positions
-      local marker_len = #('[-%-%]') + #removed_text
+      local marker_len = #'[-%-%]' + #removed_text
       cleaned_text = cleaned_text:gsub('%[%-' .. vim.pesc(removed_text) .. '%-%]', '', 1)
 
       -- Since we're removing text, we don't add highlights for removed content in the actual pane
@@ -41,20 +41,20 @@ local function parse_diff_line(text)
     local start_pos = final_text:find('{%+' .. vim.pesc(added_text) .. '%+}', 1, false)
     if start_pos then
       -- Calculate position after previous highlights
-      local highlight_start = start_pos - offset - 1  -- 0-based for extmarks
+      local highlight_start = start_pos - offset - 1 -- 0-based for extmarks
       local highlight_end = highlight_start + #added_text
 
       table.insert(final_highlights, {
         line = 0, -- Will be set by caller
         col_start = highlight_start,
         col_end = highlight_end,
-        highlight_group = 'CpDiffAdded'
+        highlight_group = 'CpDiffAdded',
       })
 
       -- Remove the marker
-      local marker_len = #{'{+'} + #{'+}'} + #added_text
+      local marker_len = #{ '{+' } + #{ '+}' } + #added_text
       final_text = final_text:gsub('{%+' .. vim.pesc(added_text) .. '%+}', added_text, 1)
-      offset = offset + #{'{+'} + #{'+}'}
+      offset = offset + #{ '{+' } + #{ '+}' }
     end
   end
 
@@ -73,13 +73,16 @@ function M.parse_git_diff(diff_output)
   local content_started = false
   for _, line in ipairs(lines) do
     -- Skip header lines (@@, +++, ---, index, etc.)
-    if content_started or (
-      not line:match('^@@') and
-      not line:match('^%+%+%+') and
-      not line:match('^%-%-%-') and
-      not line:match('^index') and
-      not line:match('^diff %-%-git')
-    ) then
+    if
+      content_started
+      or (
+        not line:match('^@@')
+        and not line:match('^%+%+%+')
+        and not line:match('^%-%-%-')
+        and not line:match('^index')
+        and not line:match('^diff %-%-git')
+      )
+    then
       content_started = true
 
       -- Process content lines
@@ -115,7 +118,7 @@ function M.parse_git_diff(diff_output)
 
   return {
     content = content_lines,
-    highlights = all_highlights
+    highlights = all_highlights,
   }
 end
 
@@ -161,4 +164,4 @@ function M.parse_and_apply_diff(bufnr, diff_output, namespace)
   return parsed.content
 end
 
-return M
\ No newline at end of file
+return M
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index c16f185..f0e4e61 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -193,7 +193,7 @@ local function toggle_test_panel(is_debug)
 
   -- Set buffer options
   local buffer_opts = { 'bufhidden', 'wipe' }
-  for _, buf in ipairs({tab_buf, expected_buf, actual_buf}) do
+  for _, buf in ipairs({ tab_buf, expected_buf, actual_buf }) do
     vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
     vim.api.nvim_set_option_value('readonly', true, { buf = buf })
     vim.api.nvim_set_option_value('modifiable', false, { buf = buf })
@@ -295,7 +295,11 @@ local function toggle_test_panel(is_debug)
       if backend.name == 'git' then
         local diff_result = backend.render(current_test.expected, current_test.actual)
         if diff_result.raw_diff and diff_result.raw_diff ~= '' then
-          highlight.parse_and_apply_diff(test_buffers.actual_buf, diff_result.raw_diff, diff_namespace)
+          highlight.parse_and_apply_diff(
+            test_buffers.actual_buf,
+            diff_result.raw_diff,
+            diff_namespace
+          )
         else
           update_buffer_content(test_buffers.actual_buf, actual_lines)
         end
diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index 5ca1298..904b445 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -49,7 +49,9 @@ function M.render_test_list(test_state, config)
     table.insert(lines, line)
 
     if is_current and test_case.input and test_case.input ~= '' then
-      for _, input_line in ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false })) do
+      for _, input_line in
+        ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false }))
+      do
         table.insert(lines, '  ' .. input_line)
       end
     end

From 5ca6b8b272ce6fe4c56a989812f2d6e409db74e4 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 12:31:19 -0400
Subject: [PATCH 04/31] feat: more stuff

---
 doc/cp.txt             | 48 +++++++++++++++++++++++++----------------
 lua/cp/config.lua      | 49 ++++++++++++++++++++++++------------------
 lua/cp/execute.lua     |  2 +-
 lua/cp/init.lua        | 11 ++++++----
 lua/cp/test.lua        |  2 +-
 lua/cp/test_render.lua |  7 +-----
 6 files changed, 67 insertions(+), 52 deletions(-)

diff --git a/doc/cp.txt b/doc/cp.txt
index 4e8f3ac..1404d65 100644
--- a/doc/cp.txt
+++ b/doc/cp.txt
@@ -85,7 +85,7 @@ Optional configuration with lazy.nvim: >
                   'g++', '-std=c++{version}', '-O2', '-Wall', '-Wextra',
                   '-DLOCAL', '{source}', '-o', '{binary}',
                 },
-                run = { '{binary}' },
+                test = { '{binary}' },
                 debug = {
                   'g++', '-std=c++{version}', '-g3',
                   '-fsanitize=address,undefined', '-DLOCAL',
@@ -95,7 +95,7 @@ Optional configuration with lazy.nvim: >
                 extension = "cc",
               },
               python = {
-                run = { 'python3', '{source}' },
+                test = { 'python3', '{source}' },
                 debug = { 'python3', '{source}' },
                 extension = "py",
               },
@@ -104,11 +104,8 @@ Optional configuration with lazy.nvim: >
             },
           },
           hooks = {
-            before_run = function(ctx) vim.cmd.w() end,
-            before_debug = function(ctx)
-              -- ctx.problem_id, ctx.platform, ctx.source_file, etc.
-              vim.cmd.w()
-            end,
+            before_test = function(ctx) vim.cmd.w() end,
+            before_debug = function(ctx) ... end,
             setup_code = function(ctx)
               vim.wo.foldmethod = "marker"
               vim.wo.foldmarker = "{{{,}}}"
@@ -116,9 +113,10 @@ Optional configuration with lazy.nvim: >
             end,
           },
           test_panel = {
-            diff_mode = "vim",        -- "vim" or "git"
-            toggle_key = "t",         -- key to toggle test panel
-            status_format = "compact", -- "compact" or "verbose"
+            diff_mode = "vim",         -- "vim" or "git"
+            toggle_key = "t",          -- toggle test panel
+            next_test_key = "<c-n>",   -- navigate to next test case
+            prev_test_key = "<c-p>",   -- navigate to previous test case
           },
           diff = {
             git = {
@@ -126,9 +124,6 @@ Optional configuration with lazy.nvim: >
               args = {"diff", "--no-index", "--word-diff=plain",
                      "--word-diff-regex=.", "--no-prefix"},
             },
-            vim = {
-              enable_diffthis = true,
-            },
           },
           snippets = { ... },  -- LuaSnip snippets
           filename = function(contest, contest_id, problem_id, config, language) ... end,
@@ -168,7 +163,7 @@ Optional configuration with lazy.nvim: >
     Fields: ~
       • {compile}?      (`string[]`) Compile command template with
                         `{version}`, `{source}`, `{binary}` placeholders.
-      • {run}           (`string[]`) Run command template.
+      • {test}          (`string[]`) Test execution command template.
       • {debug}?        (`string[]`) Debug compile command template.
       • {version}?      (`number`) Language version (e.g. 20, 23 for C++).
       • {extension}     (`string`) File extension (e.g. "cc", "py").
@@ -180,23 +175,38 @@ Optional configuration with lazy.nvim: >
       • {diff_mode}     (`string`, default: `"vim"`) Diff backend: "vim" or "git".
                         Git provides character-level precision, vim uses built-in diff.
       • {toggle_key}    (`string`, default: `"t"`) Key to toggle test panel.
-      • {status_format} (`string`, default: `"compact"`) Status display format.
+      • {next_test_key} (`string`, default: `"<c-n>"`) Key to navigate to next test case.
+      • {prev_test_key} (`string`, default: `"<c-p>"`) Key to navigate to previous test case.
 
 *cp.DiffConfig*
 
     Fields: ~
       • {git}           (`DiffGitConfig`) Git diff backend configuration.
-      • {vim}           (`DiffVimConfig`) Vim diff backend configuration.
 
 *cp.Hooks*
 
     Fields: ~
+      • {before_test}?  (`function`) Called before test panel opens.
+                        `function(ctx: ProblemContext)`
       • {before_debug}? (`function`) Called before debug compilation.
                         `function(ctx: ProblemContext)`
       • {setup_code}?   (`function`) Called after source file is opened.
-                        Used to configure buffer settings.
+                        Good for configuring buffer settings.
                         `function(ctx: ProblemContext)`
 
+*ProblemContext*
+
+    Fields: ~
+      • {contest}       (`string`) Platform name (e.g. "atcoder", "codeforces")
+      • {contest_id}    (`string`) Contest ID (e.g. "abc123", "1933")
+      • {problem_id}?   (`string`) Problem ID (e.g. "a", "b") - nil for CSES
+      • {source_file}   (`string`) Source filename (e.g. "abc123a.cpp")
+      • {binary_file}   (`string`) Binary output path (e.g. "build/abc123a.run")
+      • {input_file}    (`string`) Test input path (e.g. "io/abc123a.cpin")
+      • {output_file}   (`string`) Program output path (e.g. "io/abc123a.cpout")
+      • {expected_file} (`string`) Expected output path (e.g. "io/abc123a.expected")
+      • {problem_name}  (`string`) Display name (e.g. "abc123a")
+
 WORKFLOW                                            *cp-workflow*
 
 For the sake of consistency and simplicity, cp.nvim extracts contest/problem identifiers from
@@ -328,8 +338,8 @@ Test cases use competitive programming terminology:
 
 Keymaps ~
                                                 *cp-test-keys*
-<c-n>                           Navigate to next test case
-<c-p>                           Navigate to previous test case
+<c-n>                           Navigate to next test case (configurable via test_panel.next_test_key)
+<c-p>                           Navigate to previous test case (configurable via test_panel.prev_test_key)
 q                               Exit test panel (restore layout)
 t                               Toggle test panel (configurable via test_panel.toggle_key)
 
diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index ca82b99..6c67c95 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -1,6 +1,6 @@
 ---@class LanguageConfig
 ---@field compile? string[] Compile command template
----@field run string[] Run command template
+---@field test string[] Test execution command template
 ---@field debug? string[] Debug command template
 ---@field executable? string Executable name
 ---@field version? number Language version
@@ -8,7 +8,7 @@
 
 ---@class PartialLanguageConfig
 ---@field compile? string[] Compile command template
----@field run? string[] Run command template
+---@field test? string[] Test execution command template
 ---@field debug? string[] Debug command template
 ---@field executable? string Executable name
 ---@field version? number Language version
@@ -27,25 +27,22 @@
 ---@field timeout_ms? number
 
 ---@class Hooks
----@field before_run? fun(ctx: ProblemContext)
+---@field before_test? fun(ctx: ProblemContext)
 ---@field before_debug? fun(ctx: ProblemContext)
 ---@field setup_code? fun(ctx: ProblemContext)
 
 ---@class TestPanelConfig
 ---@field diff_mode "vim"|"git" Diff backend to use
 ---@field toggle_key string Key to toggle test panel
----@field status_format "compact"|"verbose" Status display format
+---@field next_test_key string Key to navigate to next test case
+---@field prev_test_key string Key to navigate to previous test case
 
 ---@class DiffGitConfig
 ---@field command string Git executable name
 ---@field args string[] Additional git diff arguments
 
----@class DiffVimConfig
----@field enable_diffthis boolean Enable vim's diffthis
-
 ---@class DiffConfig
 ---@field git DiffGitConfig
----@field vim DiffVimConfig
 
 ---@class cp.Config
 ---@field contests table<string, ContestConfig>
@@ -75,7 +72,7 @@ M.defaults = {
   contests = {},
   snippets = {},
   hooks = {
-    before_run = nil,
+    before_test = nil,
     before_debug = nil,
     setup_code = nil,
   },
@@ -85,16 +82,14 @@ M.defaults = {
   test_panel = {
     diff_mode = 'vim',
     toggle_key = 't',
-    status_format = 'compact',
+    next_test_key = '<c-n>',
+    prev_test_key = '<c-p>',
   },
   diff = {
     git = {
       command = 'git',
       args = { 'diff', '--no-index', '--word-diff=plain', '--word-diff-regex=.', '--no-prefix' },
     },
-    vim = {
-      enable_diffthis = true,
-    },
   },
 }
 
@@ -119,8 +114,8 @@ function M.setup(user_config)
 
     if user_config.hooks then
       vim.validate({
-        before_run = {
-          user_config.hooks.before_run,
+        before_test = {
+          user_config.hooks.before_test,
           { 'function', 'nil' },
           true,
         },
@@ -146,13 +141,26 @@ function M.setup(user_config)
           end,
           "diff_mode must be 'vim' or 'git'",
         },
-        toggle_key = { user_config.test_panel.toggle_key, 'string', true },
-        status_format = {
-          user_config.test_panel.status_format,
+        toggle_key = {
+          user_config.test_panel.toggle_key,
           function(value)
-            return vim.tbl_contains({ 'compact', 'verbose' }, value)
+            return type(value) == 'string' and value ~= ''
           end,
-          "status_format must be 'compact' or 'verbose'",
+          'toggle_key must be a non-empty string',
+        },
+        next_test_key = {
+          user_config.test_panel.next_test_key,
+          function(value)
+            return type(value) == 'string' and value ~= ''
+          end,
+          'next_test_key must be a non-empty string',
+        },
+        prev_test_key = {
+          user_config.test_panel.prev_test_key,
+          function(value)
+            return type(value) == 'string' and value ~= ''
+          end,
+          'prev_test_key must be a non-empty string',
         },
       })
     end
@@ -160,7 +168,6 @@ function M.setup(user_config)
     if user_config.diff then
       vim.validate({
         git = { user_config.diff.git, { 'table', 'nil' }, true },
-        vim = { user_config.diff.vim, { 'table', 'nil' }, true },
       })
     end
 
diff --git a/lua/cp/execute.lua b/lua/cp/execute.lua
index 1d25b87..3c7a2bf 100644
--- a/lua/cp/execute.lua
+++ b/lua/cp/execute.lua
@@ -278,7 +278,7 @@ function M.run_problem(ctx, contest_config, is_debug)
     input_data = table.concat(vim.fn.readfile(ctx.input_file), '\n') .. '\n'
   end
 
-  local run_cmd = build_command(language_config.run, language_config.executable, substitutions)
+  local run_cmd = build_command(language_config.test, language_config.executable, substitutions)
   local exec_result = execute_command(run_cmd, input_data, contest_config.timeout_ms)
   local formatted_output = format_output(exec_result, ctx.expected_file, is_debug)
 
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index f0e4e61..0792b37 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -232,7 +232,7 @@ local function toggle_test_panel(is_debug)
     local test_render = require('cp.test_render')
     test_render.setup_highlights()
     local test_state = test_module.get_test_panel_state()
-    return test_render.render_test_list(test_state, config.test_panel)
+    return test_render.render_test_list(test_state)
   end
 
   local function update_buffer_content(bufnr, lines)
@@ -305,7 +305,6 @@ local function toggle_test_panel(is_debug)
         end
       else
         update_buffer_content(test_buffers.actual_buf, actual_lines)
-        vim.api.nvim_set_option_value('diff', true, { win = test_windows.expected_win })
         vim.api.nvim_set_option_value('diff', true, { win = test_windows.actual_win })
         vim.api.nvim_win_call(test_windows.expected_win, function()
           vim.cmd.diffthis()
@@ -349,10 +348,10 @@ local function toggle_test_panel(is_debug)
     refresh_test_panel()
   end
 
-  vim.keymap.set('n', '<c-n>', function()
+  vim.keymap.set('n', config.test_panel.next_test_key, function()
     navigate_test_case(1)
   end, { buffer = test_buffers.tab_buf, silent = true })
-  vim.keymap.set('n', '<c-p>', function()
+  vim.keymap.set('n', config.test_panel.prev_test_key, function()
     navigate_test_case(-1)
   end, { buffer = test_buffers.tab_buf, silent = true })
 
@@ -365,6 +364,10 @@ local function toggle_test_panel(is_debug)
     end, { buffer = buf, silent = true })
   end
 
+  if config.hooks and config.hooks.before_test then
+    config.hooks.before_test(ctx)
+  end
+
   if is_debug and config.hooks and config.hooks.before_debug then
     config.hooks.before_debug(ctx)
   end
diff --git a/lua/cp/test.lua b/lua/cp/test.lua
index a1fdd85..e4719e6 100644
--- a/lua/cp/test.lua
+++ b/lua/cp/test.lua
@@ -172,7 +172,7 @@ local function run_single_test_case(ctx, contest_config, test_case)
     end
   end
 
-  local run_cmd = build_command(language_config.run, language_config.executable, substitutions)
+  local run_cmd = build_command(language_config.test, language_config.executable, substitutions)
 
   local stdin_content = test_case.input .. '\n'
 
diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index 904b445..9bf92c9 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -1,6 +1,3 @@
----@class TestRenderConfig
----@field status_format "compact"|"verbose"
-
 ---@class StatusInfo
 ---@field text string
 ---@field highlight_group string
@@ -32,10 +29,8 @@ end
 
 ---Render test cases list with improved layout
 ---@param test_state TestPanelState
----@param config? TestRenderConfig
 ---@return string[]
-function M.render_test_list(test_state, config)
-  config = config or { status_format = 'compact' }
+function M.render_test_list(test_state)
   local lines = {}
 
   for i, test_case in ipairs(test_state.test_cases) do

From 56c52124ec9a1c1d564818d7e67b43ebc4b358ef Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 12:36:04 -0400
Subject: [PATCH 05/31] feat: some more tests, a checkpoint

---
 lua/cp/test_render.lua    |  2 +-
 spec/config_spec.lua      | 59 ++++++++++++++++++++++++++++++++++++++-
 spec/diff_spec.lua        | 42 ++++++++++++++++++++++++++++
 spec/highlight_spec.lua   | 39 ++++++++++++++++++++++++++
 spec/test_render_spec.lua | 30 ++++++++++++++++++++
 5 files changed, 170 insertions(+), 2 deletions(-)
 create mode 100644 spec/diff_spec.lua
 create mode 100644 spec/highlight_spec.lua
 create mode 100644 spec/test_render_spec.lua

diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index 9bf92c9..aa7acf1 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -13,7 +13,7 @@ local function get_status_info(test_case)
   elseif test_case.status == 'fail' then
     if test_case.timed_out then
       return { text = 'TLE', highlight_group = 'CpTestError' }
-    elseif test_case.code and test_case.code ~= 0 then
+    elseif test_case.code and test_case.code >= 128 then
       return { text = 'RTE', highlight_group = 'CpTestError' }
     else
       return { text = 'WA', highlight_group = 'CpTestError' }
diff --git a/spec/config_spec.lua b/spec/config_spec.lua
index 3b94ddf..a429ae5 100644
--- a/spec/config_spec.lua
+++ b/spec/config_spec.lua
@@ -66,13 +66,70 @@ describe('cp.config', function()
 
     it('validates hook functions', function()
       local invalid_config = {
-        hooks = { before_run = 'not_a_function' },
+        hooks = { before_test = 'not_a_function' },
       }
 
       assert.has_error(function()
         config.setup(invalid_config)
       end)
     end)
+
+    describe('test_panel config validation', function()
+      it('validates diff_mode values', function()
+        local invalid_config = {
+          test_panel = { diff_mode = 'invalid' },
+        }
+
+        assert.has_error(function()
+          config.setup(invalid_config)
+        end)
+      end)
+
+      it('validates toggle_key is non-empty string', function()
+        local invalid_config = {
+          test_panel = { toggle_key = '' },
+        }
+
+        assert.has_error(function()
+          config.setup(invalid_config)
+        end)
+      end)
+
+      it('validates next_test_key is non-empty string', function()
+        local invalid_config = {
+          test_panel = { next_test_key = nil },
+        }
+
+        assert.has_error(function()
+          config.setup(invalid_config)
+        end)
+      end)
+
+      it('validates prev_test_key is non-empty string', function()
+        local invalid_config = {
+          test_panel = { prev_test_key = '' },
+        }
+
+        assert.has_error(function()
+          config.setup(invalid_config)
+        end)
+      end)
+
+      it('accepts valid test_panel config', function()
+        local valid_config = {
+          test_panel = {
+            diff_mode = 'git',
+            toggle_key = 'x',
+            next_test_key = 'j',
+            prev_test_key = 'k',
+          },
+        }
+
+        assert.has_no.errors(function()
+          config.setup(valid_config)
+        end)
+      end)
+    end)
   end)
 
   describe('default_filename', function()
diff --git a/spec/diff_spec.lua b/spec/diff_spec.lua
new file mode 100644
index 0000000..bdfda29
--- /dev/null
+++ b/spec/diff_spec.lua
@@ -0,0 +1,42 @@
+describe('cp.diff', function()
+  local diff = require('cp.diff')
+
+  describe('get_available_backends', function()
+    it('returns vim and git backends')
+  end)
+
+  describe('get_backend', function()
+    it('returns vim backend by name')
+    it('returns git backend by name')
+    it('returns nil for invalid name')
+  end)
+
+  describe('is_git_available', function()
+    it('returns true when git command succeeds')
+    it('returns false when git command fails')
+  end)
+
+  describe('get_best_backend', function()
+    it('returns preferred backend when available')
+    it('falls back to vim when git unavailable')
+    it('defaults to vim backend')
+  end)
+
+  describe('vim backend', function()
+    it('returns content as-is')
+    it('returns nil highlights')
+  end)
+
+  describe('git backend', function()
+    it('creates temp files for diff')
+    it('returns raw diff output')
+    it('cleans up temp files')
+    it('handles no differences')
+    it('handles git command failure')
+  end)
+
+  describe('render_diff', function()
+    it('uses best available backend')
+    it('passes parameters to backend')
+  end)
+end)
diff --git a/spec/highlight_spec.lua b/spec/highlight_spec.lua
new file mode 100644
index 0000000..5df7dd1
--- /dev/null
+++ b/spec/highlight_spec.lua
@@ -0,0 +1,39 @@
+describe('cp.highlight', function()
+  local highlight = require('cp.highlight')
+
+  describe('parse_diff_line', function()
+    it('parses added text markers {+text+}')
+    it('removes removed text markers [-text-]')
+    it('handles mixed add/remove markers')
+    it('calculates correct highlight positions')
+    it('handles text without markers')
+    it('handles empty text')
+  end)
+
+  describe('parse_git_diff', function()
+    it('skips git diff headers')
+    it('processes added lines')
+    it('ignores removed lines')
+    it('handles unchanged lines')
+    it('sets correct line numbers')
+    it('handles empty diff output')
+  end)
+
+  describe('apply_highlights', function()
+    it('clears existing highlights')
+    it('applies extmarks with correct positions')
+    it('uses correct highlight groups')
+    it('handles empty highlights')
+  end)
+
+  describe('create_namespace', function()
+    it('creates unique namespace')
+  end)
+
+  describe('parse_and_apply_diff', function()
+    it('parses diff and applies to buffer')
+    it('sets buffer content')
+    it('applies highlights')
+    it('returns content lines')
+  end)
+end)
diff --git a/spec/test_render_spec.lua b/spec/test_render_spec.lua
new file mode 100644
index 0000000..e1d5ea1
--- /dev/null
+++ b/spec/test_render_spec.lua
@@ -0,0 +1,30 @@
+describe('cp.test_render', function()
+  local test_render = require('cp.test_render')
+
+  describe('get_status_info', function()
+    it('returns AC for pass status')
+    it('returns WA for fail status with non-zero code')
+    it('returns TLE for timeout status')
+    it('returns RTE for fail with zero code')
+    it('returns empty for pending status')
+  end)
+
+  describe('render_test_list', function()
+    it('renders test cases with CP terminology')
+    it('shows current test with > prefix')
+    it('displays input only for current test')
+    it('handles empty test cases')
+    it('preserves input line breaks')
+  end)
+
+  describe('render_status_bar', function()
+    it('formats time and exit code')
+    it('handles missing time')
+    it('handles missing exit code')
+    it('returns empty for nil test case')
+  end)
+
+  describe('setup_highlights', function()
+    it('sets up all highlight groups')
+  end)
+end)

From 093782330a5b6a73a65d8d2271bb7108468a0ca8 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 12:36:15 -0400
Subject: [PATCH 06/31] feat: some more tests, a checkpoint

---
 spec/test_render_spec.lua | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/spec/test_render_spec.lua b/spec/test_render_spec.lua
index e1d5ea1..4398599 100644
--- a/spec/test_render_spec.lua
+++ b/spec/test_render_spec.lua
@@ -3,9 +3,9 @@ describe('cp.test_render', function()
 
   describe('get_status_info', function()
     it('returns AC for pass status')
-    it('returns WA for fail status with non-zero code')
+    it('returns WA for fail status with normal exit codes')
     it('returns TLE for timeout status')
-    it('returns RTE for fail with zero code')
+    it('returns RTE for fail with signal codes (>= 128)')
     it('returns empty for pending status')
   end)
 

From 21407be376e8ea80f81d869cb36a779aeab60013 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 13:19:22 -0400
Subject: [PATCH 07/31] feat(test): rest of test suite

---
 spec/diff_spec.lua        | 159 +++++++++++++++++++++++++++++----
 spec/highlight_spec.lua   | 183 +++++++++++++++++++++++++++++++++-----
 spec/test_render_spec.lua | 154 ++++++++++++++++++++++++++++----
 3 files changed, 439 insertions(+), 57 deletions(-)

diff --git a/spec/diff_spec.lua b/spec/diff_spec.lua
index bdfda29..d5b7dd4 100644
--- a/spec/diff_spec.lua
+++ b/spec/diff_spec.lua
@@ -2,41 +2,164 @@ describe('cp.diff', function()
   local diff = require('cp.diff')
 
   describe('get_available_backends', function()
-    it('returns vim and git backends')
+    it('returns vim and git backends', function()
+      local backends = diff.get_available_backends()
+      assert.same({'vim', 'git'}, backends)
+    end)
   end)
 
   describe('get_backend', function()
-    it('returns vim backend by name')
-    it('returns git backend by name')
-    it('returns nil for invalid name')
+    it('returns vim backend by name', function()
+      local backend = diff.get_backend('vim')
+      assert.is_not_nil(backend)
+      assert.equals('vim', backend.name)
+    end)
+
+    it('returns git backend by name', function()
+      local backend = diff.get_backend('git')
+      assert.is_not_nil(backend)
+      assert.equals('git', backend.name)
+    end)
+
+    it('returns nil for invalid name', function()
+      local backend = diff.get_backend('invalid')
+      assert.is_nil(backend)
+    end)
   end)
 
   describe('is_git_available', function()
-    it('returns true when git command succeeds')
-    it('returns false when git command fails')
+    it('returns true when git command succeeds', function()
+      local mock_system = stub(vim, 'system')
+      mock_system.returns({ code = 0 })
+
+      local result = diff.is_git_available()
+      assert.is_true(result)
+
+      mock_system:revert()
+    end)
+
+    it('returns false when git command fails', function()
+      local mock_system = stub(vim, 'system')
+      mock_system.returns({ code = 1 })
+
+      local result = diff.is_git_available()
+      assert.is_false(result)
+
+      mock_system:revert()
+    end)
   end)
 
   describe('get_best_backend', function()
-    it('returns preferred backend when available')
-    it('falls back to vim when git unavailable')
-    it('defaults to vim backend')
+    it('returns preferred backend when available', function()
+      local mock_is_available = stub(diff, 'is_git_available')
+      mock_is_available.returns(true)
+
+      local backend = diff.get_best_backend('git')
+      assert.equals('git', backend.name)
+
+      mock_is_available:revert()
+    end)
+
+    it('falls back to vim when git unavailable', function()
+      local mock_is_available = stub(diff, 'is_git_available')
+      mock_is_available.returns(false)
+
+      local backend = diff.get_best_backend('git')
+      assert.equals('vim', backend.name)
+
+      mock_is_available:revert()
+    end)
+
+    it('defaults to vim backend', function()
+      local backend = diff.get_best_backend()
+      assert.equals('vim', backend.name)
+    end)
   end)
 
   describe('vim backend', function()
-    it('returns content as-is')
-    it('returns nil highlights')
+    it('returns content as-is', function()
+      local backend = diff.get_backend('vim')
+      local result = backend.render('expected', 'actual')
+
+      assert.same({'actual'}, result.content)
+      assert.is_nil(result.highlights)
+    end)
   end)
 
   describe('git backend', function()
-    it('creates temp files for diff')
-    it('returns raw diff output')
-    it('cleans up temp files')
-    it('handles no differences')
-    it('handles git command failure')
+    it('creates temp files for diff', function()
+      local mock_system = stub(vim, 'system')
+      local mock_tempname = stub(vim.fn, 'tempname')
+      local mock_writefile = stub(vim.fn, 'writefile')
+      local mock_delete = stub(vim.fn, 'delete')
+
+      mock_tempname.returns('/tmp/expected', '/tmp/actual')
+      mock_system.returns({ code = 1, stdout = 'diff output' })
+
+      local backend = diff.get_backend('git')
+      backend.render('expected text', 'actual text')
+
+      assert.stub(mock_writefile).was_called(2)
+      assert.stub(mock_delete).was_called(2)
+
+      mock_system:revert()
+      mock_tempname:revert()
+      mock_writefile:revert()
+      mock_delete:revert()
+    end)
+
+    it('returns raw diff output', function()
+      local mock_system = stub(vim, 'system')
+      local mock_tempname = stub(vim.fn, 'tempname')
+      local mock_writefile = stub(vim.fn, 'writefile')
+      local mock_delete = stub(vim.fn, 'delete')
+
+      mock_tempname.returns('/tmp/expected', '/tmp/actual')
+      mock_system.returns({ code = 1, stdout = 'git diff output' })
+
+      local backend = diff.get_backend('git')
+      local result = backend.render('expected', 'actual')
+
+      assert.equals('git diff output', result.raw_diff)
+
+      mock_system:revert()
+      mock_tempname:revert()
+      mock_writefile:revert()
+      mock_delete:revert()
+    end)
+
+    it('handles no differences', function()
+      local mock_system = stub(vim, 'system')
+      local mock_tempname = stub(vim.fn, 'tempname')
+      local mock_writefile = stub(vim.fn, 'writefile')
+      local mock_delete = stub(vim.fn, 'delete')
+
+      mock_tempname.returns('/tmp/expected', '/tmp/actual')
+      mock_system.returns({ code = 0 })
+
+      local backend = diff.get_backend('git')
+      local result = backend.render('same', 'same')
+
+      assert.same({'same'}, result.content)
+      assert.same({}, result.highlights)
+
+      mock_system:revert()
+      mock_tempname:revert()
+      mock_writefile:revert()
+      mock_delete:revert()
+    end)
   end)
 
   describe('render_diff', function()
-    it('uses best available backend')
-    it('passes parameters to backend')
+    it('uses best available backend', function()
+      local mock_get_best = spy.on(diff, 'get_best_backend')
+      local mock_backend = { render = function() return {} end }
+      mock_get_best.returns(mock_backend)
+
+      diff.render_diff('expected', 'actual', 'vim')
+
+      assert.spy(mock_get_best).was_called_with('vim')
+      mock_get_best:revert()
+    end)
   end)
 end)
diff --git a/spec/highlight_spec.lua b/spec/highlight_spec.lua
index 5df7dd1..ec14d43 100644
--- a/spec/highlight_spec.lua
+++ b/spec/highlight_spec.lua
@@ -1,39 +1,174 @@
 describe('cp.highlight', function()
   local highlight = require('cp.highlight')
 
-  describe('parse_diff_line', function()
-    it('parses added text markers {+text+}')
-    it('removes removed text markers [-text-]')
-    it('handles mixed add/remove markers')
-    it('calculates correct highlight positions')
-    it('handles text without markers')
-    it('handles empty text')
-  end)
-
   describe('parse_git_diff', function()
-    it('skips git diff headers')
-    it('processes added lines')
-    it('ignores removed lines')
-    it('handles unchanged lines')
-    it('sets correct line numbers')
-    it('handles empty diff output')
+    it('skips git diff headers', function()
+      local diff_output = [[
+diff --git a/test b/test
+index 1234567..abcdefg 100644
+--- a/test
++++ b/test
+@@ -1,3 +1,3 @@
+ hello
++world
+-goodbye
+]]
+      local result = highlight.parse_git_diff(diff_output)
+      assert.same({'hello', 'world'}, result.content)
+    end)
+
+    it('processes added lines', function()
+      local diff_output = '+hello w{+o+}rld'
+      local result = highlight.parse_git_diff(diff_output)
+      assert.same({'hello world'}, result.content)
+      assert.equals(1, #result.highlights)
+      assert.equals('CpDiffAdded', result.highlights[1].highlight_group)
+    end)
+
+    it('ignores removed lines', function()
+      local diff_output = 'hello\n-removed line\n+kept line'
+      local result = highlight.parse_git_diff(diff_output)
+      assert.same({'hello', 'kept line'}, result.content)
+    end)
+
+    it('handles unchanged lines', function()
+      local diff_output = 'unchanged line\n+added line'
+      local result = highlight.parse_git_diff(diff_output)
+      assert.same({'unchanged line', 'added line'}, result.content)
+    end)
+
+    it('sets correct line numbers', function()
+      local diff_output = '+first {+added+}\n+second {+text+}'
+      local result = highlight.parse_git_diff(diff_output)
+      assert.equals(0, result.highlights[1].line)
+      assert.equals(1, result.highlights[2].line)
+    end)
+
+    it('handles empty diff output', function()
+      local result = highlight.parse_git_diff('')
+      assert.same({}, result.content)
+      assert.same({}, result.highlights)
+    end)
   end)
 
   describe('apply_highlights', function()
-    it('clears existing highlights')
-    it('applies extmarks with correct positions')
-    it('uses correct highlight groups')
-    it('handles empty highlights')
+    it('clears existing highlights', function()
+      local mock_clear = spy.on(vim.api, 'nvim_buf_clear_namespace')
+      local bufnr = 1
+      local namespace = 100
+
+      highlight.apply_highlights(bufnr, {}, namespace)
+
+      assert.spy(mock_clear).was_called_with(bufnr, namespace, 0, -1)
+      mock_clear:revert()
+    end)
+
+    it('applies extmarks with correct positions', function()
+      local mock_extmark = spy.on(vim.api, 'nvim_buf_set_extmark')
+      local bufnr = 1
+      local namespace = 100
+      local highlights = {
+        {
+          line = 0,
+          col_start = 5,
+          col_end = 10,
+          highlight_group = 'CpDiffAdded'
+        }
+      }
+
+      highlight.apply_highlights(bufnr, highlights, namespace)
+
+      assert.spy(mock_extmark).was_called_with(
+        bufnr, namespace, 0, 5,
+        {
+          end_col = 10,
+          hl_group = 'CpDiffAdded',
+          priority = 100
+        }
+      )
+      mock_extmark:revert()
+    end)
+
+    it('uses correct highlight groups', function()
+      local mock_extmark = spy.on(vim.api, 'nvim_buf_set_extmark')
+      local highlights = {
+        {
+          line = 0,
+          col_start = 0,
+          col_end = 5,
+          highlight_group = 'CpDiffAdded'
+        }
+      }
+
+      highlight.apply_highlights(1, highlights, 100)
+
+      local call_args = mock_extmark.calls[1].vals
+      assert.equals('CpDiffAdded', call_args[4].hl_group)
+      mock_extmark:revert()
+    end)
+
+    it('handles empty highlights', function()
+      local mock_extmark = spy.on(vim.api, 'nvim_buf_set_extmark')
+
+      highlight.apply_highlights(1, {}, 100)
+
+      assert.spy(mock_extmark).was_not_called()
+      mock_extmark:revert()
+    end)
   end)
 
   describe('create_namespace', function()
-    it('creates unique namespace')
+    it('creates unique namespace', function()
+      local mock_create = stub(vim.api, 'nvim_create_namespace')
+      mock_create.returns(42)
+
+      local result = highlight.create_namespace()
+
+      assert.equals(42, result)
+      assert.stub(mock_create).was_called_with('cp_diff_highlights')
+      mock_create:revert()
+    end)
   end)
 
   describe('parse_and_apply_diff', function()
-    it('parses diff and applies to buffer')
-    it('sets buffer content')
-    it('applies highlights')
-    it('returns content lines')
+    it('parses diff and applies to buffer', function()
+      local mock_set_lines = spy.on(vim.api, 'nvim_buf_set_lines')
+      local mock_apply = spy.on(highlight, 'apply_highlights')
+      local bufnr = 1
+      local namespace = 100
+      local diff_output = '+hello {+world+}'
+
+      local result = highlight.parse_and_apply_diff(bufnr, diff_output, namespace)
+
+      assert.same({'hello world'}, result)
+      assert.spy(mock_set_lines).was_called_with(bufnr, 0, -1, false, {'hello world'})
+      assert.spy(mock_apply).was_called()
+
+      mock_set_lines:revert()
+      mock_apply:revert()
+    end)
+
+    it('sets buffer content', function()
+      local mock_set_lines = spy.on(vim.api, 'nvim_buf_set_lines')
+
+      highlight.parse_and_apply_diff(1, '+test line', 100)
+
+      assert.spy(mock_set_lines).was_called_with(1, 0, -1, false, {'test line'})
+      mock_set_lines:revert()
+    end)
+
+    it('applies highlights', function()
+      local mock_apply = spy.on(highlight, 'apply_highlights')
+
+      highlight.parse_and_apply_diff(1, '+hello {+world+}', 100)
+
+      assert.spy(mock_apply).was_called()
+      mock_apply:revert()
+    end)
+
+    it('returns content lines', function()
+      local result = highlight.parse_and_apply_diff(1, '+first\n+second', 100)
+      assert.same({'first', 'second'}, result)
+    end)
   end)
 end)
diff --git a/spec/test_render_spec.lua b/spec/test_render_spec.lua
index 4398599..c8f7d91 100644
--- a/spec/test_render_spec.lua
+++ b/spec/test_render_spec.lua
@@ -2,29 +2,153 @@ describe('cp.test_render', function()
   local test_render = require('cp.test_render')
 
   describe('get_status_info', function()
-    it('returns AC for pass status')
-    it('returns WA for fail status with normal exit codes')
-    it('returns TLE for timeout status')
-    it('returns RTE for fail with signal codes (>= 128)')
-    it('returns empty for pending status')
+    it('returns AC for pass status', function()
+      local test_case = { status = 'pass' }
+      local result = test_render.get_status_info(test_case)
+      assert.equals('AC', result.text)
+      assert.equals('CpTestAC', result.highlight_group)
+    end)
+
+    it('returns WA for fail status with normal exit codes', function()
+      local test_case = { status = 'fail', code = 1 }
+      local result = test_render.get_status_info(test_case)
+      assert.equals('WA', result.text)
+      assert.equals('CpTestError', result.highlight_group)
+    end)
+
+    it('returns TLE for timeout status', function()
+      local test_case = { status = 'timeout' }
+      local result = test_render.get_status_info(test_case)
+      assert.equals('TLE', result.text)
+      assert.equals('CpTestError', result.highlight_group)
+    end)
+
+    it('returns TLE for timed out fail status', function()
+      local test_case = { status = 'fail', timed_out = true }
+      local result = test_render.get_status_info(test_case)
+      assert.equals('TLE', result.text)
+      assert.equals('CpTestError', result.highlight_group)
+    end)
+
+    it('returns RTE for fail with signal codes (>= 128)', function()
+      local test_case = { status = 'fail', code = 139 }
+      local result = test_render.get_status_info(test_case)
+      assert.equals('RTE', result.text)
+      assert.equals('CpTestError', result.highlight_group)
+    end)
+
+    it('returns empty for pending status', function()
+      local test_case = { status = 'pending' }
+      local result = test_render.get_status_info(test_case)
+      assert.equals('', result.text)
+      assert.equals('CpTestPending', result.highlight_group)
+    end)
+
+    it('returns running indicator for running status', function()
+      local test_case = { status = 'running' }
+      local result = test_render.get_status_info(test_case)
+      assert.equals('...', result.text)
+      assert.equals('CpTestPending', result.highlight_group)
+    end)
   end)
 
   describe('render_test_list', function()
-    it('renders test cases with CP terminology')
-    it('shows current test with > prefix')
-    it('displays input only for current test')
-    it('handles empty test cases')
-    it('preserves input line breaks')
+    it('renders test cases with CP terminology', function()
+      local test_state = {
+        test_cases = {
+          { status = 'pass', input = '5' },
+          { status = 'fail', code = 1, input = '3' },
+        },
+        current_index = 1,
+      }
+      local result = test_render.render_test_list(test_state)
+      assert.equals('> 1. AC', result[1])
+      assert.equals('  2. WA', result[3])
+    end)
+
+    it('shows current test with > prefix', function()
+      local test_state = {
+        test_cases = {
+          { status = 'pass', input = '' },
+          { status = 'pass', input = '' },
+        },
+        current_index = 2,
+      }
+      local result = test_render.render_test_list(test_state)
+      assert.equals('  1. AC', result[1])
+      assert.equals('> 2. AC', result[2])
+    end)
+
+    it('displays input only for current test', function()
+      local test_state = {
+        test_cases = {
+          { status = 'pass', input = '5 3' },
+          { status = 'pass', input = '2 4' },
+        },
+        current_index = 1,
+      }
+      local result = test_render.render_test_list(test_state)
+      assert.equals('> 1. AC', result[1])
+      assert.equals('  5 3', result[2])
+      assert.equals('  2. AC', result[3])
+    end)
+
+    it('handles empty test cases', function()
+      local test_state = { test_cases = {}, current_index = 1 }
+      local result = test_render.render_test_list(test_state)
+      assert.equals(0, #result)
+    end)
+
+    it('preserves input line breaks', function()
+      local test_state = {
+        test_cases = {
+          { status = 'pass', input = '5\n3\n1' },
+        },
+        current_index = 1,
+      }
+      local result = test_render.render_test_list(test_state)
+      assert.equals('> 1. AC', result[1])
+      assert.equals('  5', result[2])
+      assert.equals('  3', result[3])
+      assert.equals('  1', result[4])
+    end)
   end)
 
   describe('render_status_bar', function()
-    it('formats time and exit code')
-    it('handles missing time')
-    it('handles missing exit code')
-    it('returns empty for nil test case')
+    it('formats time and exit code', function()
+      local test_case = { time_ms = 45.7, code = 0 }
+      local result = test_render.render_status_bar(test_case)
+      assert.equals('46ms │ Exit: 0', result)
+    end)
+
+    it('handles missing time', function()
+      local test_case = { code = 0 }
+      local result = test_render.render_status_bar(test_case)
+      assert.equals('Exit: 0', result)
+    end)
+
+    it('handles missing exit code', function()
+      local test_case = { time_ms = 123 }
+      local result = test_render.render_status_bar(test_case)
+      assert.equals('123ms', result)
+    end)
+
+    it('returns empty for nil test case', function()
+      local result = test_render.render_status_bar(nil)
+      assert.equals('', result)
+    end)
   end)
 
   describe('setup_highlights', function()
-    it('sets up all highlight groups')
+    it('sets up all highlight groups', function()
+      local mock_set_hl = spy.on(vim.api, 'nvim_set_hl')
+      test_render.setup_highlights()
+
+      assert.spy(mock_set_hl).was_called(5)
+      assert.spy(mock_set_hl).was_called_with(0, 'CpTestAC', { fg = '#10b981', bold = true })
+      assert.spy(mock_set_hl).was_called_with(0, 'CpTestError', { fg = '#ef4444', bold = true })
+
+      mock_set_hl:revert()
+    end)
   end)
 end)

From 526c82cac013bfd116fdb52c6c1ef37295c98d68 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 13:19:30 -0400
Subject: [PATCH 08/31] fix(ci): format

---
 spec/diff_spec.lua      | 12 ++++++++----
 spec/highlight_spec.lua | 37 +++++++++++++++++--------------------
 2 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/spec/diff_spec.lua b/spec/diff_spec.lua
index d5b7dd4..6fef325 100644
--- a/spec/diff_spec.lua
+++ b/spec/diff_spec.lua
@@ -4,7 +4,7 @@ describe('cp.diff', function()
   describe('get_available_backends', function()
     it('returns vim and git backends', function()
       local backends = diff.get_available_backends()
-      assert.same({'vim', 'git'}, backends)
+      assert.same({ 'vim', 'git' }, backends)
     end)
   end)
 
@@ -81,7 +81,7 @@ describe('cp.diff', function()
       local backend = diff.get_backend('vim')
       local result = backend.render('expected', 'actual')
 
-      assert.same({'actual'}, result.content)
+      assert.same({ 'actual' }, result.content)
       assert.is_nil(result.highlights)
     end)
   end)
@@ -140,7 +140,7 @@ describe('cp.diff', function()
       local backend = diff.get_backend('git')
       local result = backend.render('same', 'same')
 
-      assert.same({'same'}, result.content)
+      assert.same({ 'same' }, result.content)
       assert.same({}, result.highlights)
 
       mock_system:revert()
@@ -153,7 +153,11 @@ describe('cp.diff', function()
   describe('render_diff', function()
     it('uses best available backend', function()
       local mock_get_best = spy.on(diff, 'get_best_backend')
-      local mock_backend = { render = function() return {} end }
+      local mock_backend = {
+        render = function()
+          return {}
+        end,
+      }
       mock_get_best.returns(mock_backend)
 
       diff.render_diff('expected', 'actual', 'vim')
diff --git a/spec/highlight_spec.lua b/spec/highlight_spec.lua
index ec14d43..84a7aa8 100644
--- a/spec/highlight_spec.lua
+++ b/spec/highlight_spec.lua
@@ -14,13 +14,13 @@ index 1234567..abcdefg 100644
 -goodbye
 ]]
       local result = highlight.parse_git_diff(diff_output)
-      assert.same({'hello', 'world'}, result.content)
+      assert.same({ 'hello', 'world' }, result.content)
     end)
 
     it('processes added lines', function()
       local diff_output = '+hello w{+o+}rld'
       local result = highlight.parse_git_diff(diff_output)
-      assert.same({'hello world'}, result.content)
+      assert.same({ 'hello world' }, result.content)
       assert.equals(1, #result.highlights)
       assert.equals('CpDiffAdded', result.highlights[1].highlight_group)
     end)
@@ -28,13 +28,13 @@ index 1234567..abcdefg 100644
     it('ignores removed lines', function()
       local diff_output = 'hello\n-removed line\n+kept line'
       local result = highlight.parse_git_diff(diff_output)
-      assert.same({'hello', 'kept line'}, result.content)
+      assert.same({ 'hello', 'kept line' }, result.content)
     end)
 
     it('handles unchanged lines', function()
       local diff_output = 'unchanged line\n+added line'
       local result = highlight.parse_git_diff(diff_output)
-      assert.same({'unchanged line', 'added line'}, result.content)
+      assert.same({ 'unchanged line', 'added line' }, result.content)
     end)
 
     it('sets correct line numbers', function()
@@ -72,20 +72,17 @@ index 1234567..abcdefg 100644
           line = 0,
           col_start = 5,
           col_end = 10,
-          highlight_group = 'CpDiffAdded'
-        }
+          highlight_group = 'CpDiffAdded',
+        },
       }
 
       highlight.apply_highlights(bufnr, highlights, namespace)
 
-      assert.spy(mock_extmark).was_called_with(
-        bufnr, namespace, 0, 5,
-        {
-          end_col = 10,
-          hl_group = 'CpDiffAdded',
-          priority = 100
-        }
-      )
+      assert.spy(mock_extmark).was_called_with(bufnr, namespace, 0, 5, {
+        end_col = 10,
+        hl_group = 'CpDiffAdded',
+        priority = 100,
+      })
       mock_extmark:revert()
     end)
 
@@ -96,8 +93,8 @@ index 1234567..abcdefg 100644
           line = 0,
           col_start = 0,
           col_end = 5,
-          highlight_group = 'CpDiffAdded'
-        }
+          highlight_group = 'CpDiffAdded',
+        },
       }
 
       highlight.apply_highlights(1, highlights, 100)
@@ -140,8 +137,8 @@ index 1234567..abcdefg 100644
 
       local result = highlight.parse_and_apply_diff(bufnr, diff_output, namespace)
 
-      assert.same({'hello world'}, result)
-      assert.spy(mock_set_lines).was_called_with(bufnr, 0, -1, false, {'hello world'})
+      assert.same({ 'hello world' }, result)
+      assert.spy(mock_set_lines).was_called_with(bufnr, 0, -1, false, { 'hello world' })
       assert.spy(mock_apply).was_called()
 
       mock_set_lines:revert()
@@ -153,7 +150,7 @@ index 1234567..abcdefg 100644
 
       highlight.parse_and_apply_diff(1, '+test line', 100)
 
-      assert.spy(mock_set_lines).was_called_with(1, 0, -1, false, {'test line'})
+      assert.spy(mock_set_lines).was_called_with(1, 0, -1, false, { 'test line' })
       mock_set_lines:revert()
     end)
 
@@ -168,7 +165,7 @@ index 1234567..abcdefg 100644
 
     it('returns content lines', function()
       local result = highlight.parse_and_apply_diff(1, '+first\n+second', 100)
-      assert.same({'first', 'second'}, result)
+      assert.same({ 'first', 'second' }, result)
     end)
   end)
 end)

From fa8c663f5ed0ef93bfc3ccbf042e05fd7da46f0c Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:01:17 -0400
Subject: [PATCH 09/31] fix(ci): selene erorrs

---
 lua/cp/diff.lua      | 14 +++++---------
 lua/cp/highlight.lua | 13 ++-----------
 lua/cp/init.lua      |  1 -
 3 files changed, 7 insertions(+), 21 deletions(-)

diff --git a/lua/cp/diff.lua b/lua/cp/diff.lua
index c665b78..07ea6d2 100644
--- a/lua/cp/diff.lua
+++ b/lua/cp/diff.lua
@@ -4,7 +4,7 @@
 
 ---@class DiffBackend
 ---@field name string
----@field render fun(expected: string, actual: string, mode: string?): DiffResult
+---@field render fun(expected: string, actual: string): DiffResult
 
 local M = {}
 
@@ -12,9 +12,7 @@ local M = {}
 ---@type DiffBackend
 local vim_backend = {
   name = 'vim',
-  render = function(expected, actual, mode)
-    -- For vim backend, we return the content as-is since diffthis handles highlighting
-    local expected_lines = vim.split(expected, '\n', { plain = true, trimempty = true })
+  render = function(_, actual)
     local actual_lines = vim.split(actual, '\n', { plain = true, trimempty = true })
 
     return {
@@ -28,7 +26,7 @@ local vim_backend = {
 ---@type DiffBackend
 local git_backend = {
   name = 'git',
-  render = function(expected, actual, mode)
+  render = function(expected, actual)
     -- Create temporary files for git diff
     local tmp_expected = vim.fn.tempname()
     local tmp_actual = vim.fn.tempname()
@@ -59,7 +57,6 @@ local git_backend = {
         highlights = {},
       }
     else
-      local highlight_module = require('cp.highlight')
       return {
         content = {},
         highlights = {},
@@ -114,11 +111,10 @@ end
 ---@param expected string
 ---@param actual string
 ---@param backend_name? string
----@param mode? string
 ---@return DiffResult
-function M.render_diff(expected, actual, backend_name, mode)
+function M.render_diff(expected, actual, backend_name)
   local backend = M.get_best_backend(backend_name)
-  return backend.render(expected, actual, mode)
+  return backend.render(expected, actual)
 end
 
 return M
diff --git a/lua/cp/highlight.lua b/lua/cp/highlight.lua
index 3145a15..6695d6e 100644
--- a/lua/cp/highlight.lua
+++ b/lua/cp/highlight.lua
@@ -14,7 +14,6 @@ local M = {}
 ---@param text string Raw git diff output line
 ---@return string cleaned_text, DiffHighlight[]
 local function parse_diff_line(text)
-  local highlights = {}
   local cleaned_text = text
   local offset = 0
 
@@ -22,12 +21,7 @@ local function parse_diff_line(text)
   for removed_text in text:gmatch('%[%-(.-)%-%]') do
     local start_pos = text:find('%[%-' .. vim.pesc(removed_text) .. '%-%]', 1, false)
     if start_pos then
-      -- Remove the marker and adjust positions
-      local marker_len = #'[-%-%]' + #removed_text
       cleaned_text = cleaned_text:gsub('%[%-' .. vim.pesc(removed_text) .. '%-%]', '', 1)
-
-      -- Since we're removing text, we don't add highlights for removed content in the actual pane
-      -- This is handled by showing removed content in the expected pane
     end
   end
 
@@ -52,9 +46,8 @@ local function parse_diff_line(text)
       })
 
       -- Remove the marker
-      local marker_len = #{ '{+' } + #{ '+}' } + #added_text
       final_text = final_text:gsub('{%+' .. vim.pesc(added_text) .. '%+}', added_text, 1)
-      offset = offset + #{ '{+' } + #{ '+}' }
+      offset = offset + 4 -- Length of {+ and +}
     end
   end
 
@@ -99,9 +92,7 @@ function M.parse_git_diff(diff_output)
           highlight.line = line_num - 1 -- 0-based for extmarks
           table.insert(all_highlights, highlight)
         end
-      elseif line:match('^%-') then
-        -- Removed line - we handle this in the expected pane, skip for actual
-      elseif not line:match('^\\') then -- Skip "\ No newline" messages
+      elseif not line:match('^%-') and not line:match('^\\') then -- Skip removed lines and "\ No newline" messages
         -- Unchanged line
         local parsed_line, line_highlights = parse_diff_line(line)
         table.insert(content_lines, parsed_line)
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 0792b37..50e7c25 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -192,7 +192,6 @@ local function toggle_test_panel(is_debug)
   local actual_buf = vim.api.nvim_create_buf(false, true)
 
   -- Set buffer options
-  local buffer_opts = { 'bufhidden', 'wipe' }
   for _, buf in ipairs({ tab_buf, expected_buf, actual_buf }) do
     vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
     vim.api.nvim_set_option_value('readonly', true, { buf = buf })

From 1fbac30332631449ad777eacba53a8b0a0b69f1a Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:04:37 -0400
Subject: [PATCH 10/31] fix(ci): some type errors

---
 lua/cp/diff.lua | 1 +
 vim.toml        | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/lua/cp/diff.lua b/lua/cp/diff.lua
index 07ea6d2..2784b4b 100644
--- a/lua/cp/diff.lua
+++ b/lua/cp/diff.lua
@@ -1,6 +1,7 @@
 ---@class DiffResult
 ---@field content string[]
 ---@field highlights table[]?
+---@field raw_diff string?
 
 ---@class DiffBackend
 ---@field name string
diff --git a/vim.toml b/vim.toml
index 9a4528d..8bf26ea 100644
--- a/vim.toml
+++ b/vim.toml
@@ -22,3 +22,9 @@ any = true
 
 [after_each]
 any = true
+
+[spy]
+any = true
+
+[stub]
+any = true

From 259ab328a7ffe6a841b0c8ebaa7ccd87c41b1a33 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:08:17 -0400
Subject: [PATCH 11/31] fix(ci): use bundled table deep compares with busted

---
 lua/cp/test_render.lua |  4 ++--
 spec/diff_spec.lua     | 15 ++++++++++++---
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index aa7acf1..df3d9b3 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -7,7 +7,7 @@ local M = {}
 ---Convert test status to CP terminology with colors
 ---@param test_case TestCase
 ---@return StatusInfo
-local function get_status_info(test_case)
+function M.get_status_info(test_case)
   if test_case.status == 'pass' then
     return { text = 'AC', highlight_group = 'CpTestAC' }
   elseif test_case.status == 'fail' then
@@ -36,7 +36,7 @@ function M.render_test_list(test_state)
   for i, test_case in ipairs(test_state.test_cases) do
     local is_current = i == test_state.current_index
     local prefix = is_current and '> ' or '  '
-    local status_info = get_status_info(test_case)
+    local status_info = M.get_status_info(test_case)
 
     local status_text = status_info.text ~= '' and status_info.text or ''
     local line = string.format('%s%d. %s', prefix, i, status_text)
diff --git a/spec/diff_spec.lua b/spec/diff_spec.lua
index 6fef325..95097ee 100644
--- a/spec/diff_spec.lua
+++ b/spec/diff_spec.lua
@@ -4,7 +4,8 @@ describe('cp.diff', function()
   describe('get_available_backends', function()
     it('returns vim and git backends', function()
       local backends = diff.get_available_backends()
-      assert.same({ 'vim', 'git' }, backends)
+      table.sort(backends)
+      assert.same({ 'git', 'vim' }, backends)
     end)
   end)
 
@@ -30,7 +31,11 @@ describe('cp.diff', function()
   describe('is_git_available', function()
     it('returns true when git command succeeds', function()
       local mock_system = stub(vim, 'system')
-      mock_system.returns({ code = 0 })
+      mock_system.returns({
+        wait = function()
+          return { code = 0 }
+        end,
+      })
 
       local result = diff.is_git_available()
       assert.is_true(result)
@@ -40,7 +45,11 @@ describe('cp.diff', function()
 
     it('returns false when git command fails', function()
       local mock_system = stub(vim, 'system')
-      mock_system.returns({ code = 1 })
+      mock_system.returns({
+        wait = function()
+          return { code = 1 }
+        end,
+      })
 
       local result = diff.is_git_available()
       assert.is_false(result)

From 34d943bd1ecafbf388a86631b9548fe700733ba5 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:09:51 -0400
Subject: [PATCH 12/31] fix(test): mock vim.sytsem and other calls

---
 spec/diff_spec.lua | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/spec/diff_spec.lua b/spec/diff_spec.lua
index 95097ee..f8ac012 100644
--- a/spec/diff_spec.lua
+++ b/spec/diff_spec.lua
@@ -103,7 +103,7 @@ describe('cp.diff', function()
       local mock_delete = stub(vim.fn, 'delete')
 
       mock_tempname.returns('/tmp/expected', '/tmp/actual')
-      mock_system.returns({ code = 1, stdout = 'diff output' })
+      mock_system.returns({ wait = function() return { code = 1, stdout = 'diff output' } end })
 
       local backend = diff.get_backend('git')
       backend.render('expected text', 'actual text')
@@ -124,7 +124,7 @@ describe('cp.diff', function()
       local mock_delete = stub(vim.fn, 'delete')
 
       mock_tempname.returns('/tmp/expected', '/tmp/actual')
-      mock_system.returns({ code = 1, stdout = 'git diff output' })
+      mock_system.returns({ wait = function() return { code = 1, stdout = 'git diff output' } end })
 
       local backend = diff.get_backend('git')
       local result = backend.render('expected', 'actual')
@@ -144,7 +144,7 @@ describe('cp.diff', function()
       local mock_delete = stub(vim.fn, 'delete')
 
       mock_tempname.returns('/tmp/expected', '/tmp/actual')
-      mock_system.returns({ code = 0 })
+      mock_system.returns({ wait = function() return { code = 0 } end })
 
       local backend = diff.get_backend('git')
       local result = backend.render('same', 'same')
@@ -161,17 +161,17 @@ describe('cp.diff', function()
 
   describe('render_diff', function()
     it('uses best available backend', function()
-      local mock_get_best = spy.on(diff, 'get_best_backend')
       local mock_backend = {
         render = function()
           return {}
         end,
       }
+      local mock_get_best = stub(diff, 'get_best_backend')
       mock_get_best.returns(mock_backend)
 
       diff.render_diff('expected', 'actual', 'vim')
 
-      assert.spy(mock_get_best).was_called_with('vim')
+      assert.stub(mock_get_best).was_called_with('vim')
       mock_get_best:revert()
     end)
   end)

From 9b6df85e9e65e281e65ce20bafdd19f5afb8be02 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:11:16 -0400
Subject: [PATCH 13/31] fix(ci): stub vim.api calls

---
 lua/cp/highlight.lua    |  4 ++++
 spec/diff_spec.lua      | 18 +++++++++++++++---
 spec/highlight_spec.lua | 42 ++++++++++++++++++++++++-----------------
 3 files changed, 44 insertions(+), 20 deletions(-)

diff --git a/lua/cp/highlight.lua b/lua/cp/highlight.lua
index 6695d6e..1aa108b 100644
--- a/lua/cp/highlight.lua
+++ b/lua/cp/highlight.lua
@@ -58,6 +58,10 @@ end
 ---@param diff_output string
 ---@return ParsedDiff
 function M.parse_git_diff(diff_output)
+  if diff_output == '' then
+    return { content = {}, highlights = {} }
+  end
+
   local lines = vim.split(diff_output, '\n', { plain = true })
   local content_lines = {}
   local all_highlights = {}
diff --git a/spec/diff_spec.lua b/spec/diff_spec.lua
index f8ac012..d9ac3b3 100644
--- a/spec/diff_spec.lua
+++ b/spec/diff_spec.lua
@@ -103,7 +103,11 @@ describe('cp.diff', function()
       local mock_delete = stub(vim.fn, 'delete')
 
       mock_tempname.returns('/tmp/expected', '/tmp/actual')
-      mock_system.returns({ wait = function() return { code = 1, stdout = 'diff output' } end })
+      mock_system.returns({
+        wait = function()
+          return { code = 1, stdout = 'diff output' }
+        end,
+      })
 
       local backend = diff.get_backend('git')
       backend.render('expected text', 'actual text')
@@ -124,7 +128,11 @@ describe('cp.diff', function()
       local mock_delete = stub(vim.fn, 'delete')
 
       mock_tempname.returns('/tmp/expected', '/tmp/actual')
-      mock_system.returns({ wait = function() return { code = 1, stdout = 'git diff output' } end })
+      mock_system.returns({
+        wait = function()
+          return { code = 1, stdout = 'git diff output' }
+        end,
+      })
 
       local backend = diff.get_backend('git')
       local result = backend.render('expected', 'actual')
@@ -144,7 +152,11 @@ describe('cp.diff', function()
       local mock_delete = stub(vim.fn, 'delete')
 
       mock_tempname.returns('/tmp/expected', '/tmp/actual')
-      mock_system.returns({ wait = function() return { code = 0 } end })
+      mock_system.returns({
+        wait = function()
+          return { code = 0 }
+        end,
+      })
 
       local backend = diff.get_backend('git')
       local result = backend.render('same', 'same')
diff --git a/spec/highlight_spec.lua b/spec/highlight_spec.lua
index 84a7aa8..a83abdb 100644
--- a/spec/highlight_spec.lua
+++ b/spec/highlight_spec.lua
@@ -3,16 +3,14 @@ describe('cp.highlight', function()
 
   describe('parse_git_diff', function()
     it('skips git diff headers', function()
-      local diff_output = [[
-diff --git a/test b/test
+      local diff_output = [[diff --git a/test b/test
 index 1234567..abcdefg 100644
 --- a/test
 +++ b/test
 @@ -1,3 +1,3 @@
  hello
 +world
--goodbye
-]]
+-goodbye]]
       local result = highlight.parse_git_diff(diff_output)
       assert.same({ 'hello', 'world' }, result.content)
     end)
@@ -64,7 +62,8 @@ index 1234567..abcdefg 100644
     end)
 
     it('applies extmarks with correct positions', function()
-      local mock_extmark = spy.on(vim.api, 'nvim_buf_set_extmark')
+      local mock_extmark = stub(vim.api, 'nvim_buf_set_extmark')
+      local mock_clear = stub(vim.api, 'nvim_buf_clear_namespace')
       local bufnr = 1
       local namespace = 100
       local highlights = {
@@ -78,16 +77,18 @@ index 1234567..abcdefg 100644
 
       highlight.apply_highlights(bufnr, highlights, namespace)
 
-      assert.spy(mock_extmark).was_called_with(bufnr, namespace, 0, 5, {
+      assert.stub(mock_extmark).was_called_with(bufnr, namespace, 0, 5, {
         end_col = 10,
         hl_group = 'CpDiffAdded',
         priority = 100,
       })
       mock_extmark:revert()
+      mock_clear:revert()
     end)
 
     it('uses correct highlight groups', function()
-      local mock_extmark = spy.on(vim.api, 'nvim_buf_set_extmark')
+      local mock_extmark = stub(vim.api, 'nvim_buf_set_extmark')
+      local mock_clear = stub(vim.api, 'nvim_buf_clear_namespace')
       local highlights = {
         {
           line = 0,
@@ -102,15 +103,18 @@ index 1234567..abcdefg 100644
       local call_args = mock_extmark.calls[1].vals
       assert.equals('CpDiffAdded', call_args[4].hl_group)
       mock_extmark:revert()
+      mock_clear:revert()
     end)
 
     it('handles empty highlights', function()
-      local mock_extmark = spy.on(vim.api, 'nvim_buf_set_extmark')
+      local mock_extmark = stub(vim.api, 'nvim_buf_set_extmark')
+      local mock_clear = stub(vim.api, 'nvim_buf_clear_namespace')
 
       highlight.apply_highlights(1, {}, 100)
 
-      assert.spy(mock_extmark).was_not_called()
+      assert.stub(mock_extmark).was_not_called()
       mock_extmark:revert()
+      mock_clear:revert()
     end)
   end)
 
@@ -129,8 +133,8 @@ index 1234567..abcdefg 100644
 
   describe('parse_and_apply_diff', function()
     it('parses diff and applies to buffer', function()
-      local mock_set_lines = spy.on(vim.api, 'nvim_buf_set_lines')
-      local mock_apply = spy.on(highlight, 'apply_highlights')
+      local mock_set_lines = stub(vim.api, 'nvim_buf_set_lines')
+      local mock_apply = stub(highlight, 'apply_highlights')
       local bufnr = 1
       local namespace = 100
       local diff_output = '+hello {+world+}'
@@ -138,28 +142,32 @@ index 1234567..abcdefg 100644
       local result = highlight.parse_and_apply_diff(bufnr, diff_output, namespace)
 
       assert.same({ 'hello world' }, result)
-      assert.spy(mock_set_lines).was_called_with(bufnr, 0, -1, false, { 'hello world' })
-      assert.spy(mock_apply).was_called()
+      assert.stub(mock_set_lines).was_called_with(bufnr, 0, -1, false, { 'hello world' })
+      assert.stub(mock_apply).was_called()
 
       mock_set_lines:revert()
       mock_apply:revert()
     end)
 
     it('sets buffer content', function()
-      local mock_set_lines = spy.on(vim.api, 'nvim_buf_set_lines')
+      local mock_set_lines = stub(vim.api, 'nvim_buf_set_lines')
+      local mock_apply = stub(highlight, 'apply_highlights')
 
       highlight.parse_and_apply_diff(1, '+test line', 100)
 
-      assert.spy(mock_set_lines).was_called_with(1, 0, -1, false, { 'test line' })
+      assert.stub(mock_set_lines).was_called_with(1, 0, -1, false, { 'test line' })
       mock_set_lines:revert()
+      mock_apply:revert()
     end)
 
     it('applies highlights', function()
-      local mock_apply = spy.on(highlight, 'apply_highlights')
+      local mock_set_lines = stub(vim.api, 'nvim_buf_set_lines')
+      local mock_apply = stub(highlight, 'apply_highlights')
 
       highlight.parse_and_apply_diff(1, '+hello {+world+}', 100)
 
-      assert.spy(mock_apply).was_called()
+      assert.stub(mock_apply).was_called()
+      mock_set_lines:revert()
       mock_apply:revert()
     end)
 

From 1049e60736aa1f6cf67f6e6daffb95970e87058f Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:14:12 -0400
Subject: [PATCH 14/31] fix(ci): use proper deep compare

---
 lua/cp/highlight.lua    | 5 +++--
 spec/highlight_spec.lua | 7 +++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/lua/cp/highlight.lua b/lua/cp/highlight.lua
index 1aa108b..2a60fe0 100644
--- a/lua/cp/highlight.lua
+++ b/lua/cp/highlight.lua
@@ -97,8 +97,9 @@ function M.parse_git_diff(diff_output)
           table.insert(all_highlights, highlight)
         end
       elseif not line:match('^%-') and not line:match('^\\') then -- Skip removed lines and "\ No newline" messages
-        -- Unchanged line
-        local parsed_line, line_highlights = parse_diff_line(line)
+        -- Unchanged line - remove leading space if present
+        local clean_line = line:match('^%s') and line:sub(2) or line
+        local parsed_line, line_highlights = parse_diff_line(clean_line)
         table.insert(content_lines, parsed_line)
 
         -- Set line numbers for any highlights (shouldn't be any for unchanged lines)
diff --git a/spec/highlight_spec.lua b/spec/highlight_spec.lua
index a83abdb..d1b2ad2 100644
--- a/spec/highlight_spec.lua
+++ b/spec/highlight_spec.lua
@@ -100,8 +100,11 @@ index 1234567..abcdefg 100644
 
       highlight.apply_highlights(1, highlights, 100)
 
-      local call_args = mock_extmark.calls[1].vals
-      assert.equals('CpDiffAdded', call_args[4].hl_group)
+      assert.stub(mock_extmark).was_called_with(1, 100, 0, 0, {
+        end_col = 5,
+        hl_group = 'CpDiffAdded',
+        priority = 100,
+      })
       mock_extmark:revert()
       mock_clear:revert()
     end)

From bf7fc52efccbf12b8e3d70fc4521a1a18e087a3a Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:32:34 -0400
Subject: [PATCH 15/31] fix: table-based rendering

---
 lua/cp/execute.lua     |  6 ++++++
 lua/cp/highlight.lua   | 11 ++++++++---
 lua/cp/init.lua        | 37 +++++++++++++++++++++++++---------
 lua/cp/test_render.lua | 45 +++++++++++++++++++++++++++++++-----------
 4 files changed, 75 insertions(+), 24 deletions(-)

diff --git a/lua/cp/execute.lua b/lua/cp/execute.lua
index 3c7a2bf..b59a954 100644
--- a/lua/cp/execute.lua
+++ b/lua/cp/execute.lua
@@ -284,7 +284,13 @@ function M.run_problem(ctx, contest_config, is_debug)
 
   local output_buf = vim.fn.bufnr(ctx.output_file)
   if output_buf ~= -1 then
+    local was_modifiable = vim.api.nvim_get_option_value('modifiable', { buf = output_buf })
+    local was_readonly = vim.api.nvim_get_option_value('readonly', { buf = output_buf })
+    vim.api.nvim_set_option_value('readonly', false, { buf = output_buf })
+    vim.api.nvim_set_option_value('modifiable', true, { buf = output_buf })
     vim.api.nvim_buf_set_lines(output_buf, 0, -1, false, vim.split(formatted_output, '\n'))
+    vim.api.nvim_set_option_value('modifiable', was_modifiable, { buf = output_buf })
+    vim.api.nvim_set_option_value('readonly', was_readonly, { buf = output_buf })
     vim.api.nvim_buf_call(output_buf, function()
       vim.cmd.write()
     end)
diff --git a/lua/cp/highlight.lua b/lua/cp/highlight.lua
index 2a60fe0..1f10fac 100644
--- a/lua/cp/highlight.lua
+++ b/lua/cp/highlight.lua
@@ -151,10 +151,15 @@ end
 function M.parse_and_apply_diff(bufnr, diff_output, namespace)
   local parsed = M.parse_git_diff(diff_output)
 
-  -- Set buffer content
-  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, parsed.content)
+  local was_modifiable = vim.api.nvim_get_option_value('modifiable', { buf = bufnr })
+  local was_readonly = vim.api.nvim_get_option_value('readonly', { buf = bufnr })
+
+  vim.api.nvim_set_option_value('readonly', false, { buf = bufnr })
+  vim.api.nvim_set_option_value('modifiable', true, { buf = bufnr })
+  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, parsed.content)
+  vim.api.nvim_set_option_value('modifiable', was_modifiable, { buf = bufnr })
+  vim.api.nvim_set_option_value('readonly', was_readonly, { buf = bufnr })
 
-  -- Apply highlights
   M.apply_highlights(bufnr, parsed.highlights, namespace)
 
   return parsed.content
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 50e7c25..2bd6a3e 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -227,17 +227,33 @@ local function toggle_test_panel(is_debug)
   local highlight = require('cp.highlight')
   local diff_namespace = highlight.create_namespace()
 
-  local function render_test_tabs()
-    local test_render = require('cp.test_render')
-    test_render.setup_highlights()
-    local test_state = test_module.get_test_panel_state()
-    return test_render.render_test_list(test_state)
-  end
+  local test_list_namespace = vim.api.nvim_create_namespace('cp_test_list')
 
-  local function update_buffer_content(bufnr, lines)
+  local function update_buffer_content(bufnr, lines, highlights)
+    local was_readonly = vim.api.nvim_get_option_value('readonly', { buf = bufnr })
+
+    vim.api.nvim_set_option_value('readonly', false, { buf = bufnr })
     vim.api.nvim_set_option_value('modifiable', true, { buf = bufnr })
     vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
     vim.api.nvim_set_option_value('modifiable', false, { buf = bufnr })
+    vim.api.nvim_set_option_value('readonly', was_readonly, { buf = bufnr })
+
+    if highlights then
+      vim.api.nvim_buf_clear_namespace(bufnr, test_list_namespace, 0, -1)
+      for _, highlight in ipairs(highlights) do
+        vim.api.nvim_buf_set_extmark(
+          bufnr,
+          test_list_namespace,
+          highlight.line,
+          highlight.col_start,
+          {
+            end_col = highlight.col_end,
+            hl_group = highlight.highlight_group,
+            priority = 100,
+          }
+        )
+      end
+    end
   end
 
   local function update_expected_pane()
@@ -324,8 +340,11 @@ local function toggle_test_panel(is_debug)
       return
     end
 
-    local tab_lines = render_test_tabs()
-    update_buffer_content(test_buffers.tab_buf, tab_lines)
+    local test_render = require('cp.test_render')
+    test_render.setup_highlights()
+    local test_state = test_module.get_test_panel_state()
+    local tab_lines, tab_highlights = test_render.render_test_list(test_state)
+    update_buffer_content(test_buffers.tab_buf, tab_lines, tab_highlights)
 
     update_expected_pane()
     update_actual_pane()
diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index df3d9b3..1170f09 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -27,32 +27,53 @@ function M.get_status_info(test_case)
   end
 end
 
----Render test cases list with improved layout
+---Render test cases as a clean table
 ---@param test_state TestPanelState
----@return string[]
+---@return string[], table[] lines and highlight positions
 function M.render_test_list(test_state)
   local lines = {}
+  local highlights = {}
+
+  local header = ' #  │ Status │ Time │ Exit │ Input'
+  local separator =
+    '────┼────────┼──────┼──────┼─────────────────'
+  table.insert(lines, header)
+  table.insert(lines, separator)
 
   for i, test_case in ipairs(test_state.test_cases) do
     local is_current = i == test_state.current_index
-    local prefix = is_current and '> ' or '  '
+    local prefix = is_current and '>' or ' '
     local status_info = M.get_status_info(test_case)
 
-    local status_text = status_info.text ~= '' and status_info.text or ''
-    local line = string.format('%s%d. %s', prefix, i, status_text)
+    local num_col = string.format('%s%-2d', prefix, i)
+    local status_col = string.format(' %-6s', status_info.text)
+    local time_col = test_case.time_ms and string.format('%4.0fms', test_case.time_ms) or '  —  '
+    local exit_col = test_case.code and string.format(' %-3d', test_case.code) or ' — '
+    local input_col = test_case.input and test_case.input:gsub('\n', ' ') or ''
 
+    local line = string.format(
+      '%s │%s │ %s │%s │ %s',
+      num_col,
+      status_col,
+      time_col,
+      exit_col,
+      input_col
+    )
     table.insert(lines, line)
 
-    if is_current and test_case.input and test_case.input ~= '' then
-      for _, input_line in
-        ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false }))
-      do
-        table.insert(lines, '  ' .. input_line)
-      end
+    if status_info.text ~= '' then
+      local status_start = #num_col + 3
+      local status_end = status_start + #status_info.text
+      table.insert(highlights, {
+        line = #lines - 1,
+        col_start = status_start,
+        col_end = status_end,
+        highlight_group = status_info.highlight_group,
+      })
     end
   end
 
-  return lines
+  return lines, highlights
 end
 
 ---Create status bar content for diff pane

From 44f8a3cb741b076b4f69669466c3127fb06a6ea5 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:34:11 -0400
Subject: [PATCH 16/31] fix(test): fix test panel

---
 lua/cp/init.lua | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 2bd6a3e..a6a249c 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -238,21 +238,19 @@ local function toggle_test_panel(is_debug)
     vim.api.nvim_set_option_value('modifiable', false, { buf = bufnr })
     vim.api.nvim_set_option_value('readonly', was_readonly, { buf = bufnr })
 
-    if highlights then
-      vim.api.nvim_buf_clear_namespace(bufnr, test_list_namespace, 0, -1)
-      for _, highlight in ipairs(highlights) do
-        vim.api.nvim_buf_set_extmark(
-          bufnr,
-          test_list_namespace,
-          highlight.line,
-          highlight.col_start,
-          {
-            end_col = highlight.col_end,
-            hl_group = highlight.highlight_group,
-            priority = 100,
-          }
-        )
-      end
+    vim.api.nvim_buf_clear_namespace(bufnr, test_list_namespace, 0, -1)
+    for _, highlight in ipairs(highlights) do
+      vim.api.nvim_buf_set_extmark(
+        bufnr,
+        test_list_namespace,
+        highlight.line,
+        highlight.col_start,
+        {
+          end_col = highlight.col_end,
+          hl_group = highlight.highlight_group,
+          priority = 100,
+        }
+      )
     end
   end
 
@@ -267,7 +265,7 @@ local function toggle_test_panel(is_debug)
     local expected_text = current_test.expected
     local expected_lines = vim.split(expected_text, '\n', { plain = true, trimempty = true })
 
-    update_buffer_content(test_buffers.expected_buf, expected_lines)
+    update_buffer_content(test_buffers.expected_buf, expected_lines, {})
 
     local diff_backend = require('cp.diff')
     local backend = diff_backend.get_best_backend(config.test_panel.diff_mode)
@@ -316,10 +314,10 @@ local function toggle_test_panel(is_debug)
             diff_namespace
           )
         else
-          update_buffer_content(test_buffers.actual_buf, actual_lines)
+          update_buffer_content(test_buffers.actual_buf, actual_lines, {})
         end
       else
-        update_buffer_content(test_buffers.actual_buf, actual_lines)
+        update_buffer_content(test_buffers.actual_buf, actual_lines, {})
         vim.api.nvim_set_option_value('diff', true, { win = test_windows.actual_win })
         vim.api.nvim_win_call(test_windows.expected_win, function()
           vim.cmd.diffthis()
@@ -329,7 +327,7 @@ local function toggle_test_panel(is_debug)
         end)
       end
     else
-      update_buffer_content(test_buffers.actual_buf, actual_lines)
+      update_buffer_content(test_buffers.actual_buf, actual_lines, {})
       vim.api.nvim_set_option_value('diff', false, { win = test_windows.expected_win })
       vim.api.nvim_set_option_value('diff', false, { win = test_windows.actual_win })
     end

From ff75b975ab20856f9d52501b3c0886ade85ba17b Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:52:20 -0400
Subject: [PATCH 17/31] feat(table): refactor table with input in the middle

---
 lua/cp/test_render.lua | 48 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 41 insertions(+), 7 deletions(-)

diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index 1170f09..abf7cd0 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -4,6 +4,25 @@
 
 local M = {}
 
+local exit_code_names = {
+  [128] = 'SIGHUP',
+  [129] = 'SIGINT',
+  [130] = 'SIGQUIT',
+  [131] = 'SIGILL',
+  [132] = 'SIGTRAP',
+  [133] = 'SIGABRT',
+  [134] = 'SIGBUS',
+  [135] = 'SIGFPE',
+  [136] = 'SIGKILL',
+  [137] = 'SIGUSR1',
+  [138] = 'SIGSEGV',
+  [139] = 'SIGUSR2',
+  [140] = 'SIGPIPE',
+  [141] = 'SIGALRM',
+  [142] = 'SIGTERM',
+  [143] = 'SIGCHLD',
+}
+
 ---Convert test status to CP terminology with colors
 ---@param test_case TestCase
 ---@return StatusInfo
@@ -34,9 +53,9 @@ function M.render_test_list(test_state)
   local lines = {}
   local highlights = {}
 
-  local header = ' #  │ Status │ Time │ Exit │ Input'
+  local header = ' #  │ Status │ Time │ Exit Code'
   local separator =
-    '────┼────────┼──────┼──────┼─────────────────'
+    '────┼────────┼──────┼───────────'
   table.insert(lines, header)
   table.insert(lines, separator)
 
@@ -48,16 +67,22 @@ function M.render_test_list(test_state)
     local num_col = string.format('%s%-2d', prefix, i)
     local status_col = string.format(' %-6s', status_info.text)
     local time_col = test_case.time_ms and string.format('%4.0fms', test_case.time_ms) or '  —  '
-    local exit_col = test_case.code and string.format(' %-3d', test_case.code) or ' — '
-    local input_col = test_case.input and test_case.input:gsub('\n', ' ') or ''
+    local exit_col = ' — '
+    if test_case.code then
+      local signal_name = exit_code_names[test_case.code]
+      if signal_name then
+        exit_col = string.format(' %d (%s)', test_case.code, signal_name)
+      else
+        exit_col = string.format(' %d', test_case.code)
+      end
+    end
 
     local line = string.format(
-      '%s │%s │ %s │%s │ %s',
+      '%s │%s │ %s │%s',
       num_col,
       status_col,
       time_col,
-      exit_col,
-      input_col
+      exit_col
     )
     table.insert(lines, line)
 
@@ -71,6 +96,15 @@ function M.render_test_list(test_state)
         highlight_group = status_info.highlight_group,
       })
     end
+
+    if is_current and test_case.input and test_case.input ~= '' then
+      for _, input_line in ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false })) do
+        table.insert(lines, input_line)
+      end
+    end
+
+    local separator = '─────────────────────────────────────────────────────────────'
+    table.insert(lines, separator)
   end
 
   return lines, highlights

From 5605df8e6c4f8d85173efef1f554e6fa5d8c1613 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 14:52:25 -0400
Subject: [PATCH 18/31] fix(ci): use proper deep compare

---
 lua/cp/test_render.lua | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index abf7cd0..a8a8d96 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -77,13 +77,7 @@ function M.render_test_list(test_state)
       end
     end
 
-    local line = string.format(
-      '%s │%s │ %s │%s',
-      num_col,
-      status_col,
-      time_col,
-      exit_col
-    )
+    local line = string.format('%s │%s │ %s │%s', num_col, status_col, time_col, exit_col)
     table.insert(lines, line)
 
     if status_info.text ~= '' then
@@ -98,12 +92,15 @@ function M.render_test_list(test_state)
     end
 
     if is_current and test_case.input and test_case.input ~= '' then
-      for _, input_line in ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false })) do
+      for _, input_line in
+        ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false }))
+      do
         table.insert(lines, input_line)
       end
     end
 
-    local separator = '─────────────────────────────────────────────────────────────'
+    local separator =
+      '─────────────────────────────────────────────────────────────'
     table.insert(lines, separator)
   end
 

From 3c8b76207ce798c299170791ecc96fc38945ce71 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 16:00:40 -0400
Subject: [PATCH 19/31] feat(ci): pre-commit

---
 .github/workflows/quality.yml |   4 +-
 .pre-commit-config.yaml       |  29 ++++++++
 lua/cp/test_render.lua        |  96 +++++++++++++++++++++------
 pyproject.toml                |   1 +
 uv.lock                       | 121 ++++++++++++++++++++++++++++++++++
 5 files changed, 229 insertions(+), 22 deletions(-)
 create mode 100644 .pre-commit-config.yaml

diff --git a/.github/workflows/quality.yml b/.github/workflows/quality.yml
index fc2c8b5..c100808 100644
--- a/.github/workflows/quality.yml
+++ b/.github/workflows/quality.yml
@@ -44,7 +44,7 @@ jobs:
       - uses: JohnnyMorganz/stylua-action@v4
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          version: latest
+          version: 2.1.0
           args: --check .
 
   lua-lint:
@@ -114,4 +114,4 @@ jobs:
       - name: Install dependencies with mypy
         run: uv sync --dev
       - name: Type check Python files with mypy
-        run: uv run mypy scrapers/ tests/scrapers/
\ No newline at end of file
+        run: uv run mypy scrapers/ tests/scrapers/
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..4acb307
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,29 @@
+minimum_pre_commit_version: "3.5.0"
+repos:
+  - repo: https://github.com/JohnnyMorganz/StyLua
+    rev: v2.1.0
+    hooks:
+      - id: stylua-github
+        name: stylua (Lua formatter)
+        args: ["--check", "."]
+        files: ^(lua/|spec/|plugin/|after/|ftdetect/|.*\.lua$)
+        additional_dependencies: []
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.6.9
+    hooks:
+      - id: ruff-format
+        name: ruff (format)
+        files: ^(scrapers/|tests/scrapers/|.*\.py$)
+      - id: ruff
+        name: ruff (lint)
+        args: ["--no-fix"]
+        files: ^(scrapers/|tests/scrapers/|.*\.py$)
+  - repo: local
+    hooks:
+      - id: mypy
+        name: mypy (type check)
+        entry: uv run mypy
+        language: system
+        args: ["scrapers/", "tests/scrapers/"]
+        files: ^(scrapers/|tests/scrapers/|.*\.py$)
+        pass_filenames: false
diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index a8a8d96..b0ad842 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -46,6 +46,49 @@ function M.get_status_info(test_case)
   end
 end
 
+local function format_exit_code(code)
+  if not code then
+    return '—'
+  end
+  local signal_name = exit_code_names[code]
+  if signal_name then
+    return string.format('%d (%s)', code, signal_name)
+  else
+    return tostring(code)
+  end
+end
+
+local function calculate_column_widths(test_state)
+  local widths = { num = 3, status = 6, time = 4, exit = 4 }
+
+  for i, test_case in ipairs(test_state.test_cases) do
+    local prefix = i == test_state.current_index and '>' or ' '
+    local num_text = string.format('%s%d', prefix, i)
+    widths.num = math.max(widths.num, #num_text)
+
+    local status_info = M.get_status_info(test_case)
+    widths.status = math.max(widths.status, #status_info.text)
+
+    local time_text = test_case.time_ms and string.format('%dms', test_case.time_ms) or '—'
+    widths.time = math.max(widths.time, #time_text)
+
+    local exit_text = format_exit_code(test_case.code)
+    widths.exit = math.max(widths.exit, #exit_text)
+  end
+
+  return widths
+end
+
+local function create_separator(widths)
+  local parts = {
+    string.rep('─', widths.num),
+    string.rep('─', widths.status),
+    string.rep('─', widths.time),
+    string.rep('─', widths.exit),
+  }
+  return table.concat(parts, '┼')
+end
+
 ---Render test cases as a clean table
 ---@param test_state TestPanelState
 ---@return string[], table[] lines and highlight positions
@@ -53,9 +96,21 @@ function M.render_test_list(test_state)
   local lines = {}
   local highlights = {}
 
-  local header = ' #  │ Status │ Time │ Exit Code'
-  local separator =
-    '────┼────────┼──────┼───────────'
+  local widths = calculate_column_widths(test_state)
+  local separator = create_separator(widths)
+
+  local header = string.format(
+    '%-*s│%-*s│%-*s│%-*s',
+    widths.num,
+    ' #',
+    widths.status,
+    ' Status',
+    widths.time,
+    ' Time',
+    widths.exit,
+    ' Exit Code'
+  )
+
   table.insert(lines, header)
   table.insert(lines, separator)
 
@@ -64,24 +119,26 @@ function M.render_test_list(test_state)
     local prefix = is_current and '>' or ' '
     local status_info = M.get_status_info(test_case)
 
-    local num_col = string.format('%s%-2d', prefix, i)
-    local status_col = string.format(' %-6s', status_info.text)
-    local time_col = test_case.time_ms and string.format('%4.0fms', test_case.time_ms) or '  —  '
-    local exit_col = ' — '
-    if test_case.code then
-      local signal_name = exit_code_names[test_case.code]
-      if signal_name then
-        exit_col = string.format(' %d (%s)', test_case.code, signal_name)
-      else
-        exit_col = string.format(' %d', test_case.code)
-      end
-    end
+    local num_text = string.format('%s%d', prefix, i)
+    local time_text = test_case.time_ms and string.format('%dms', test_case.time_ms) or '—'
+    local exit_text = format_exit_code(test_case.code)
 
-    local line = string.format('%s │%s │ %s │%s', num_col, status_col, time_col, exit_col)
-    table.insert(lines, line)
+    local row = string.format(
+      '%-*s│ %-*s│%-*s│ %-*s',
+      widths.num,
+      num_text,
+      widths.status - 1,
+      status_info.text,
+      widths.time,
+      time_text,
+      widths.exit - 1,
+      exit_text
+    )
+
+    table.insert(lines, row)
 
     if status_info.text ~= '' then
-      local status_start = #num_col + 3
+      local status_start = widths.num + 2
       local status_end = status_start + #status_info.text
       table.insert(highlights, {
         line = #lines - 1,
@@ -92,6 +149,7 @@ function M.render_test_list(test_state)
     end
 
     if is_current and test_case.input and test_case.input ~= '' then
+      table.insert(lines, separator)
       for _, input_line in
         ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false }))
       do
@@ -99,8 +157,6 @@ function M.render_test_list(test_state)
       end
     end
 
-    local separator =
-      '─────────────────────────────────────────────────────────────'
     table.insert(lines, separator)
   end
 
diff --git a/pyproject.toml b/pyproject.toml
index 289baf0..5c731b5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -17,6 +17,7 @@ dev = [
     "types-requests>=2.32.4.20250913",
     "pytest>=8.0.0",
     "pytest-mock>=3.12.0",
+    "pre-commit>=4.3.0",
 ]
 
 [tool.pytest.ini_options]
diff --git a/uv.lock b/uv.lock
index bfe4d6d..744b4ae 100644
--- a/uv.lock
+++ b/uv.lock
@@ -24,6 +24,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/e5/48/1549795ba7742c948d2ad169c1c8cdbae65bc450d6cd753d124b17c8cd32/certifi-2025.8.3-py3-none-any.whl", hash = "sha256:f6c12493cfb1b06ba2ff328595af9350c65d6644968e5d3a2ffd78699af217a5", size = 161216, upload-time = "2025-08-03T03:07:45.777Z" },
 ]
 
+[[package]]
+name = "cfgv"
+version = "3.4.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/11/74/539e56497d9bd1d484fd863dd69cbbfa653cd2aa27abfe35653494d85e94/cfgv-3.4.0.tar.gz", hash = "sha256:e52591d4c5f5dead8e0f673fb16db7949d2cfb3f7da4582893288f0ded8fe560", size = 7114, upload-time = "2023-08-12T20:38:17.776Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/c5/55/51844dd50c4fc7a33b653bfaba4c2456f06955289ca770a5dbd5fd267374/cfgv-3.4.0-py2.py3-none-any.whl", hash = "sha256:b7265b1f29fd3316bfcd2b330d63d024f2bfd8bcb8b0272f8e19a504856c48f9", size = 7249, upload-time = "2023-08-12T20:38:16.269Z" },
+]
+
 [[package]]
 name = "charset-normalizer"
 version = "3.4.3"
@@ -100,6 +109,33 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/d1/d6/3965ed04c63042e047cb6a3e6ed1a63a35087b6a609aa3a15ed8ac56c221/colorama-0.4.6-py2.py3-none-any.whl", hash = "sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6", size = 25335, upload-time = "2022-10-25T02:36:20.889Z" },
 ]
 
+[[package]]
+name = "distlib"
+version = "0.4.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/96/8e/709914eb2b5749865801041647dc7f4e6d00b549cfe88b65ca192995f07c/distlib-0.4.0.tar.gz", hash = "sha256:feec40075be03a04501a973d81f633735b4b69f98b05450592310c0f401a4e0d", size = 614605, upload-time = "2025-07-17T16:52:00.465Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/33/6b/e0547afaf41bf2c42e52430072fa5658766e3d65bd4b03a563d1b6336f57/distlib-0.4.0-py2.py3-none-any.whl", hash = "sha256:9659f7d87e46584a30b5780e43ac7a2143098441670ff0a49d5f9034c54a6c16", size = 469047, upload-time = "2025-07-17T16:51:58.613Z" },
+]
+
+[[package]]
+name = "filelock"
+version = "3.19.1"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/40/bb/0ab3e58d22305b6f5440629d20683af28959bf793d98d11950e305c1c326/filelock-3.19.1.tar.gz", hash = "sha256:66eda1888b0171c998b35be2bcc0f6d75c388a7ce20c3f3f37aa8e96c2dddf58", size = 17687, upload-time = "2025-08-14T16:56:03.016Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/42/14/42b2651a2f46b022ccd948bca9f2d5af0fd8929c4eec235b8d6d844fbe67/filelock-3.19.1-py3-none-any.whl", hash = "sha256:d38e30481def20772f5baf097c122c3babc4fcdb7e14e57049eb9d88c6dc017d", size = 15988, upload-time = "2025-08-14T16:56:01.633Z" },
+]
+
+[[package]]
+name = "identify"
+version = "2.6.14"
+source = { registry = "https://pypi.org/simple" }
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 name = "requests"
 version = "2.32.5"
@@ -278,6 +383,7 @@ dependencies = [
 [package.dev-dependencies]
 dev = [
     { name = "mypy" },
+    { name = "pre-commit" },
     { name = "pytest" },
     { name = "pytest-mock" },
     { name = "types-beautifulsoup4" },
@@ -294,6 +400,7 @@ requires-dist = [
 [package.metadata.requires-dev]
 dev = [
     { name = "mypy", specifier = ">=1.18.2" },
+    { name = "pre-commit", specifier = ">=4.3.0" },
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     { name = "pytest-mock", specifier = ">=3.12.0" },
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From 7a850ab228b968e1d916b4b7d8239d6bdd4f0aef Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 18:40:19 -0400
Subject: [PATCH 20/31] fix(test): table rendering

---
 lua/cp/init.lua        |   6 -
 lua/cp/test_render.lua | 280 ++++++++++++++++++++++++++---------------
 2 files changed, 181 insertions(+), 105 deletions(-)

diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index a6a249c..81d55a0 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -295,12 +295,6 @@ local function toggle_test_panel(is_debug)
       actual_lines = { '(not run yet)' }
     end
 
-    local test_render = require('cp.test_render')
-    local status_bar_text = test_render.render_status_bar(current_test)
-    if status_bar_text ~= '' then
-      vim.api.nvim_set_option_value('winbar', status_bar_text, { win = test_windows.actual_win })
-    end
-
     if enable_diff then
       local diff_backend = require('cp.diff')
       local backend = diff_backend.get_best_backend(config.test_panel.diff_mode)
diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index b0ad842..fad2836 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -23,7 +23,6 @@ local exit_code_names = {
   [143] = 'SIGCHLD',
 }
 
----Convert test status to CP terminology with colors
 ---@param test_case TestCase
 ---@return StatusInfo
 function M.get_status_info(test_case)
@@ -51,140 +50,224 @@ local function format_exit_code(code)
     return '—'
   end
   local signal_name = exit_code_names[code]
-  if signal_name then
-    return string.format('%d (%s)', code, signal_name)
-  else
-    return tostring(code)
-  end
+  return signal_name and string.format('%d (%s)', code, signal_name) or tostring(code)
 end
 
-local function calculate_column_widths(test_state)
-  local widths = { num = 3, status = 6, time = 4, exit = 4 }
+-- Compute column widths + aggregates
+local function compute_cols(test_state)
+  local w = { num = 3, status = 8, time = 6, exit = 11 }
 
-  for i, test_case in ipairs(test_state.test_cases) do
-    local prefix = i == test_state.current_index and '>' or ' '
-    local num_text = string.format('%s%d', prefix, i)
-    widths.num = math.max(widths.num, #num_text)
-
-    local status_info = M.get_status_info(test_case)
-    widths.status = math.max(widths.status, #status_info.text)
-
-    local time_text = test_case.time_ms and string.format('%dms', test_case.time_ms) or '—'
-    widths.time = math.max(widths.time, #time_text)
-
-    local exit_text = format_exit_code(test_case.code)
-    widths.exit = math.max(widths.exit, #exit_text)
+  for i, tc in ipairs(test_state.test_cases) do
+    local prefix = (i == test_state.current_index) and '>' or ' '
+    w.num = math.max(w.num, #(prefix .. i))
+    w.status = math.max(w.status, #(' ' .. M.get_status_info(tc).text))
+    local time_str = tc.time_ms and (string.format('%.2f', tc.time_ms) .. 'ms') or '—'
+    w.time = math.max(w.time, #time_str)
+    w.exit = math.max(w.exit, #(' ' .. format_exit_code(tc.code)))
   end
 
-  return widths
+  w.num = math.max(w.num, #' #')
+  w.status = math.max(w.status, #' Status')
+  w.time = math.max(w.time, #' Time')
+  w.exit = math.max(w.exit, #' Exit Code')
+
+  local sum = w.num + w.status + w.time + w.exit
+  local inner = sum + 3 -- three inner vertical dividers
+  local total = inner + 2 -- two outer borders
+  return { w = w, sum = sum, inner = inner, total = total }
 end
 
-local function create_separator(widths)
-  local parts = {
-    string.rep('─', widths.num),
-    string.rep('─', widths.status),
-    string.rep('─', widths.time),
-    string.rep('─', widths.exit),
-  }
-  return table.concat(parts, '┼')
+local function center(text, width)
+  local pad = width - #text
+  if pad <= 0 then
+    return text
+  end
+  local left = math.floor(pad / 2)
+  return string.rep(' ', left) .. text .. string.rep(' ', pad - left)
+end
+
+local function top_border(c)
+  local w = c.w
+  return '┌'
+    .. string.rep('─', w.num)
+    .. '┬'
+    .. string.rep('─', w.status)
+    .. '┬'
+    .. string.rep('─', w.time)
+    .. '┬'
+    .. string.rep('─', w.exit)
+    .. '┐'
+end
+
+local function row_sep(c)
+  local w = c.w
+  return '├'
+    .. string.rep('─', w.num)
+    .. '┼'
+    .. string.rep('─', w.status)
+    .. '┼'
+    .. string.rep('─', w.time)
+    .. '┼'
+    .. string.rep('─', w.exit)
+    .. '┤'
+end
+
+local function bottom_border(c)
+  local w = c.w
+  return '└'
+    .. string.rep('─', w.num)
+    .. '┴'
+    .. string.rep('─', w.status)
+    .. '┴'
+    .. string.rep('─', w.time)
+    .. '┴'
+    .. string.rep('─', w.exit)
+    .. '┘'
+end
+
+local function flat_fence_above(c)
+  local w = c.w
+  return '├'
+    .. string.rep('─', w.num)
+    .. '┴'
+    .. string.rep('─', w.status)
+    .. '┴'
+    .. string.rep('─', w.time)
+    .. '┴'
+    .. string.rep('─', w.exit)
+    .. '┤'
+end
+
+local function flat_fence_below(c)
+  local w = c.w
+  return '├'
+    .. string.rep('─', w.num)
+    .. '┬'
+    .. string.rep('─', w.status)
+    .. '┬'
+    .. string.rep('─', w.time)
+    .. '┬'
+    .. string.rep('─', w.exit)
+    .. '┤'
+end
+
+local function flat_bottom_border(c)
+  return '└' .. string.rep('─', c.inner) .. '┘'
+end
+
+local function header_line(c)
+  local w = c.w
+  return '│'
+    .. center('#', w.num)
+    .. '│'
+    .. center('Status', w.status)
+    .. '│'
+    .. center('Time', w.time)
+    .. '│'
+    .. center('Exit Code', w.exit)
+    .. '│'
+end
+
+local function data_row(c, idx, tc, is_current)
+  local w = c.w
+  local prefix = is_current and '>' or ' '
+  local status = M.get_status_info(tc)
+  local time = tc.time_ms and (string.format('%.2f', tc.time_ms) .. 'ms') or '—'
+  local exit = format_exit_code(tc.code)
+
+  local line = '│'
+    .. center(prefix .. idx, w.num)
+    .. '│'
+    .. center(status.text, w.status)
+    .. '│'
+    .. center(time, w.time)
+    .. '│'
+    .. center(exit, w.exit)
+    .. '│'
+
+  local hi
+  if status.text ~= '' then
+    local pad = w.status - #status.text
+    local left = math.floor(pad / 2)
+    local status_start_col = 1 + w.num + 1 + left
+    local status_end_col = status_start_col + #status.text
+    hi = {
+      col_start = status_start_col,
+      col_end = status_end_col,
+      highlight_group = status.highlight_group,
+    }
+  end
+
+  return line, hi
 end
 
----Render test cases as a clean table
 ---@param test_state TestPanelState
 ---@return string[], table[] lines and highlight positions
 function M.render_test_list(test_state)
-  local lines = {}
-  local highlights = {}
+  local lines, highlights = {}, {}
+  local c = compute_cols(test_state)
 
-  local widths = calculate_column_widths(test_state)
-  local separator = create_separator(widths)
-
-  local header = string.format(
-    '%-*s│%-*s│%-*s│%-*s',
-    widths.num,
-    ' #',
-    widths.status,
-    ' Status',
-    widths.time,
-    ' Time',
-    widths.exit,
-    ' Exit Code'
-  )
-
-  table.insert(lines, header)
-  table.insert(lines, separator)
-
-  for i, test_case in ipairs(test_state.test_cases) do
-    local is_current = i == test_state.current_index
-    local prefix = is_current and '>' or ' '
-    local status_info = M.get_status_info(test_case)
-
-    local num_text = string.format('%s%d', prefix, i)
-    local time_text = test_case.time_ms and string.format('%dms', test_case.time_ms) or '—'
-    local exit_text = format_exit_code(test_case.code)
-
-    local row = string.format(
-      '%-*s│ %-*s│%-*s│ %-*s',
-      widths.num,
-      num_text,
-      widths.status - 1,
-      status_info.text,
-      widths.time,
-      time_text,
-      widths.exit - 1,
-      exit_text
-    )
+  table.insert(lines, top_border(c))
+  table.insert(lines, header_line(c))
+  table.insert(lines, row_sep(c))
 
+  for i, tc in ipairs(test_state.test_cases) do
+    local is_current = (i == test_state.current_index)
+    local row, hi = data_row(c, i, tc, is_current)
     table.insert(lines, row)
-
-    if status_info.text ~= '' then
-      local status_start = widths.num + 2
-      local status_end = status_start + #status_info.text
-      table.insert(highlights, {
-        line = #lines - 1,
-        col_start = status_start,
-        col_end = status_end,
-        highlight_group = status_info.highlight_group,
-      })
+    if hi then
+      hi.line = #lines - 1
+      table.insert(highlights, hi)
     end
 
-    if is_current and test_case.input and test_case.input ~= '' then
-      table.insert(lines, separator)
-      for _, input_line in
-        ipairs(vim.split(test_case.input, '\n', { plain = true, trimempty = false }))
-      do
-        table.insert(lines, input_line)
+    local has_next = (i < #test_state.test_cases)
+    local has_input = is_current and tc.input and tc.input ~= ''
+
+    if has_input then
+      table.insert(lines, flat_fence_above(c))
+
+      for _, input_line in ipairs(vim.split(tc.input, '\n', { plain = true, trimempty = false })) do
+        local s = input_line or ''
+        if #s > c.inner then
+          s = string.sub(s, 1, c.inner)
+        end
+        local pad = c.inner - #s
+        table.insert(lines, '│' .. s .. string.rep(' ', pad) .. '│')
+      end
+
+      if has_next then
+        table.insert(lines, flat_fence_below(c))
+      else
+        table.insert(lines, flat_bottom_border(c))
+      end
+    else
+      if has_next then
+        table.insert(lines, row_sep(c))
+      else
+        table.insert(lines, bottom_border(c))
       end
     end
-
-    table.insert(lines, separator)
   end
 
   return lines, highlights
 end
 
----Create status bar content for diff pane
 ---@param test_case TestCase?
 ---@return string
 function M.render_status_bar(test_case)
   if not test_case then
     return ''
   end
-
   local parts = {}
-
   if test_case.time_ms then
-    table.insert(parts, string.format('%.0fms', test_case.time_ms))
+    table.insert(parts, string.format('%.2fms', test_case.time_ms))
   end
-
   if test_case.code then
     table.insert(parts, string.format('Exit: %d', test_case.code))
   end
-
   return table.concat(parts, ' │ ')
 end
 
----Get highlight groups needed for test rendering
 ---@return table<string, table>
 function M.get_highlight_groups()
   return {
@@ -196,11 +279,10 @@ function M.get_highlight_groups()
   }
 end
 
----Setup highlight groups
 function M.setup_highlights()
   local groups = M.get_highlight_groups()
-  for group_name, opts in pairs(groups) do
-    vim.api.nvim_set_hl(0, group_name, opts)
+  for name, opts in pairs(groups) do
+    vim.api.nvim_set_hl(0, name, opts)
   end
 end
 

From 2b9e55f07700da0bca658a593a832ad771104698 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 18:46:00 -0400
Subject: [PATCH 21/31] fix(ci): fix the tests

---
 lua/cp/init.lua           | 18 +++++----------
 selene.toml               |  2 +-
 spec/test_render_spec.lua | 47 ++++++++++++++++++++++++++-------------
 3 files changed, 38 insertions(+), 29 deletions(-)

diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 81d55a0..a27af41 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -239,18 +239,12 @@ local function toggle_test_panel(is_debug)
     vim.api.nvim_set_option_value('readonly', was_readonly, { buf = bufnr })
 
     vim.api.nvim_buf_clear_namespace(bufnr, test_list_namespace, 0, -1)
-    for _, highlight in ipairs(highlights) do
-      vim.api.nvim_buf_set_extmark(
-        bufnr,
-        test_list_namespace,
-        highlight.line,
-        highlight.col_start,
-        {
-          end_col = highlight.col_end,
-          hl_group = highlight.highlight_group,
-          priority = 100,
-        }
-      )
+    for _, hl in ipairs(highlights) do
+      vim.api.nvim_buf_set_extmark(bufnr, test_list_namespace, hl.line, hl.col_start, {
+        end_col = hl.col_end,
+        hl_group = hl.highlight_group,
+        priority = 100,
+      })
     end
   end
 
diff --git a/selene.toml b/selene.toml
index d03ab0a..96cf5ab 100644
--- a/selene.toml
+++ b/selene.toml
@@ -1 +1 @@
-std = "vim"
+std = 'vim'
diff --git a/spec/test_render_spec.lua b/spec/test_render_spec.lua
index c8f7d91..c68c95a 100644
--- a/spec/test_render_spec.lua
+++ b/spec/test_render_spec.lua
@@ -53,7 +53,7 @@ describe('cp.test_render', function()
   end)
 
   describe('render_test_list', function()
-    it('renders test cases with CP terminology', function()
+    it('renders table with headers and borders', function()
       local test_state = {
         test_cases = {
           { status = 'pass', input = '5' },
@@ -62,11 +62,12 @@ describe('cp.test_render', function()
         current_index = 1,
       }
       local result = test_render.render_test_list(test_state)
-      assert.equals('> 1. AC', result[1])
-      assert.equals('  2. WA', result[3])
+      assert.is_true(result[1]:match('^┌'))
+      assert.is_true(result[2]:match('│.*#.*│.*Status.*│.*Time.*│.*Exit Code.*│'))
+      assert.is_true(result[3]:match('^├'))
     end)
 
-    it('shows current test with > prefix', function()
+    it('shows current test with > prefix in table', function()
       local test_state = {
         test_cases = {
           { status = 'pass', input = '' },
@@ -75,8 +76,14 @@ describe('cp.test_render', function()
         current_index = 2,
       }
       local result = test_render.render_test_list(test_state)
-      assert.equals('  1. AC', result[1])
-      assert.equals('> 2. AC', result[2])
+      local found_current = false
+      for _, line in ipairs(result) do
+        if line:match('│.*>2.*│') then
+          found_current = true
+          break
+        end
+      end
+      assert.is_true(found_current)
     end)
 
     it('displays input only for current test', function()
@@ -88,15 +95,20 @@ describe('cp.test_render', function()
         current_index = 1,
       }
       local result = test_render.render_test_list(test_state)
-      assert.equals('> 1. AC', result[1])
-      assert.equals('  5 3', result[2])
-      assert.equals('  2. AC', result[3])
+      local found_input = false
+      for _, line in ipairs(result) do
+        if line:match('│5 3') then
+          found_input = true
+          break
+        end
+      end
+      assert.is_true(found_input)
     end)
 
     it('handles empty test cases', function()
       local test_state = { test_cases = {}, current_index = 1 }
       local result = test_render.render_test_list(test_state)
-      assert.equals(0, #result)
+      assert.equals(3, #result)
     end)
 
     it('preserves input line breaks', function()
@@ -107,10 +119,13 @@ describe('cp.test_render', function()
         current_index = 1,
       }
       local result = test_render.render_test_list(test_state)
-      assert.equals('> 1. AC', result[1])
-      assert.equals('  5', result[2])
-      assert.equals('  3', result[3])
-      assert.equals('  1', result[4])
+      local input_lines = {}
+      for _, line in ipairs(result) do
+        if line:match('^│[531]') then
+          table.insert(input_lines, line:match('│([531])'))
+        end
+      end
+      assert.same({ '5', '3', '1' }, input_lines)
     end)
   end)
 
@@ -118,7 +133,7 @@ describe('cp.test_render', function()
     it('formats time and exit code', function()
       local test_case = { time_ms = 45.7, code = 0 }
       local result = test_render.render_status_bar(test_case)
-      assert.equals('46ms │ Exit: 0', result)
+      assert.equals('45.70ms │ Exit: 0', result)
     end)
 
     it('handles missing time', function()
@@ -130,7 +145,7 @@ describe('cp.test_render', function()
     it('handles missing exit code', function()
       local test_case = { time_ms = 123 }
       local result = test_render.render_status_bar(test_case)
-      assert.equals('123ms', result)
+      assert.equals('123.00ms', result)
     end)
 
     it('returns empty for nil test case', function()

From 8bd570b89e892e4f69cbaa3323adeff32054c459 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 18:48:06 -0400
Subject: [PATCH 22/31] fix(ci): final testh

---
 spec/test_render_spec.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spec/test_render_spec.lua b/spec/test_render_spec.lua
index c68c95a..6e29201 100644
--- a/spec/test_render_spec.lua
+++ b/spec/test_render_spec.lua
@@ -62,7 +62,7 @@ describe('cp.test_render', function()
         current_index = 1,
       }
       local result = test_render.render_test_list(test_state)
-      assert.is_true(result[1]:match('^┌'))
+      assert.is_true(result[1]:find('^┌') ~= nil)
       assert.is_true(result[2]:match('│.*#.*│.*Status.*│.*Time.*│.*Exit Code.*│'))
       assert.is_true(result[3]:match('^├'))
     end)

From ef3d39c7f4690c1bd52f9baa6f8e6ca852246bbd Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 18:48:10 -0400
Subject: [PATCH 23/31] fix(ci): final testh

---
 spec/test_render_spec.lua | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/spec/test_render_spec.lua b/spec/test_render_spec.lua
index 6e29201..f7ace52 100644
--- a/spec/test_render_spec.lua
+++ b/spec/test_render_spec.lua
@@ -63,8 +63,8 @@ describe('cp.test_render', function()
       }
       local result = test_render.render_test_list(test_state)
       assert.is_true(result[1]:find('^┌') ~= nil)
-      assert.is_true(result[2]:match('│.*#.*│.*Status.*│.*Time.*│.*Exit Code.*│'))
-      assert.is_true(result[3]:match('^├'))
+      assert.is_true(result[2]:find('│.*#.*│.*Status.*│.*Time.*│.*Exit Code.*│') ~= nil)
+      assert.is_true(result[3]:find('^├') ~= nil)
     end)
 
     it('shows current test with > prefix in table', function()

From dd6bf47684fb4770ad8398ce98b6894d13ef2777 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 18:53:39 -0400
Subject: [PATCH 24/31] feat: :CP test -> :CP run

---
 doc/cp.txt                    | 25 +++++++++-----------
 lua/cp/config.lua             | 27 ++++++++--------------
 lua/cp/init.lua               | 43 ++++++++++++++++-------------------
 lua/cp/test.lua               | 22 +++++++++---------
 lua/cp/test_render.lua        |  2 +-
 spec/command_parsing_spec.lua | 12 +++++-----
 spec/config_spec.lua          | 23 +++++--------------
 7 files changed, 64 insertions(+), 90 deletions(-)

diff --git a/doc/cp.txt b/doc/cp.txt
index 1404d65..8229fbf 100644
--- a/doc/cp.txt
+++ b/doc/cp.txt
@@ -49,7 +49,7 @@ Setup Commands ~
 
 Action Commands ~
 
-:CP test [--debug]              Toggle test panel for individual test case
+:CP run [--debug]               Toggle run panel for individual test case
                                 debugging. Shows per-test results with redesigned
                                 layout for efficient comparison.
                                 Use --debug flag to compile with debug flags
@@ -112,9 +112,8 @@ Optional configuration with lazy.nvim: >
               vim.diagnostic.enable(false)
             end,
           },
-          test_panel = {
+          run_panel = {
             diff_mode = "vim",         -- "vim" or "git"
-            toggle_key = "t",          -- toggle test panel
             next_test_key = "<c-n>",   -- navigate to next test case
             prev_test_key = "<c-p>",   -- navigate to previous test case
           },
@@ -141,7 +140,7 @@ Optional configuration with lazy.nvim: >
                         during operation.
       • {scrapers}      (`table<string,boolean>`) Per-platform scraper control.
                          Default enables all platforms.
-      • {test_panel}    (`TestPanelConfig`) Test panel behavior configuration.
+      • {run_panel}     (`RunPanelConfig`) Test panel behavior configuration.
       • {diff}          (`DiffConfig`) Diff backend configuration.
       • {filename}?     (`function`) Custom filename generation function.
                         `function(contest, contest_id, problem_id, config, language)`
@@ -169,12 +168,11 @@ Optional configuration with lazy.nvim: >
       • {extension}     (`string`) File extension (e.g. "cc", "py").
       • {executable}?   (`string`) Executable name for interpreted languages.
 
-*cp.TestPanelConfig*
+*cp.RunPanelConfig*
 
     Fields: ~
       • {diff_mode}     (`string`, default: `"vim"`) Diff backend: "vim" or "git".
                         Git provides character-level precision, vim uses built-in diff.
-      • {toggle_key}    (`string`, default: `"t"`) Key to toggle test panel.
       • {next_test_key} (`string`, default: `"<c-n>"`) Key to navigate to next test case.
       • {prev_test_key} (`string`, default: `"<c-p>"`) Key to navigate to previous test case.
 
@@ -295,15 +293,15 @@ Example: Quick setup for single Codeforces problem >
     :CP test                    " Test immediately
 <
 
-TEST PANEL                                          *cp-test*
+RUN PANEL                                          *cp-run*
 
-The test panel provides individual test case debugging with a streamlined
+The run panel provides individual test case debugging with a streamlined
 layout optimized for modern screens. Shows test status with competitive
 programming terminology and efficient space usage.
 
 Activation ~
-                                                      *:CP-test*
-:CP test [--debug]              Toggle test panel on/off. When activated,
+                                                      *:CP-run*
+:CP run [--debug]               Toggle run panel on/off. When activated,
                                 replaces current layout with test interface.
                                 Automatically compiles and runs all tests.
                                 Use --debug flag to compile with debug symbols
@@ -312,7 +310,7 @@ Activation ~
 
 Interface ~
 
-The test panel uses a redesigned two-pane layout for efficient comparison:
+The run panel uses a redesigned two-pane layout for efficient comparison:
 (note that the diff is indeed highlighted, not the weird amalgamation of
 characters below) >
 
@@ -338,10 +336,9 @@ Test cases use competitive programming terminology:
 
 Keymaps ~
                                                 *cp-test-keys*
-<c-n>                           Navigate to next test case (configurable via test_panel.next_test_key)
-<c-p>                           Navigate to previous test case (configurable via test_panel.prev_test_key)
+<c-n>                           Navigate to next test case (configurable via run_panel.next_test_key)
+<c-p>                           Navigate to previous test case (configurable via run_panel.prev_test_key)
 q                               Exit test panel (restore layout)
-t                               Toggle test panel (configurable via test_panel.toggle_key)
 
 Diff Modes ~
 
diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index 6c67c95..225aab7 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -31,9 +31,8 @@
 ---@field before_debug? fun(ctx: ProblemContext)
 ---@field setup_code? fun(ctx: ProblemContext)
 
----@class TestPanelConfig
+---@class RunPanelConfig
 ---@field diff_mode "vim"|"git" Diff backend to use
----@field toggle_key string Key to toggle test panel
 ---@field next_test_key string Key to navigate to next test case
 ---@field prev_test_key string Key to navigate to previous test case
 
@@ -51,7 +50,7 @@
 ---@field debug boolean
 ---@field scrapers table<string, boolean>
 ---@field filename? fun(contest: string, contest_id: string, problem_id?: string, config: cp.Config, language?: string): string
----@field test_panel TestPanelConfig
+---@field run_panel RunPanelConfig
 ---@field diff DiffConfig
 
 ---@class cp.UserConfig
@@ -61,7 +60,7 @@
 ---@field debug? boolean
 ---@field scrapers? table<string, boolean>
 ---@field filename? fun(contest: string, contest_id: string, problem_id?: string, config: cp.Config, language?: string): string
----@field test_panel? TestPanelConfig
+---@field run_panel? RunPanelConfig
 ---@field diff? DiffConfig
 
 local M = {}
@@ -79,9 +78,8 @@ M.defaults = {
   debug = false,
   scrapers = constants.PLATFORMS,
   filename = nil,
-  test_panel = {
+  run_panel = {
     diff_mode = 'vim',
-    toggle_key = 't',
     next_test_key = '<c-n>',
     prev_test_key = '<c-p>',
   },
@@ -108,7 +106,7 @@ function M.setup(user_config)
       debug = { user_config.debug, { 'boolean', 'nil' }, true },
       scrapers = { user_config.scrapers, { 'table', 'nil' }, true },
       filename = { user_config.filename, { 'function', 'nil' }, true },
-      test_panel = { user_config.test_panel, { 'table', 'nil' }, true },
+      run_panel = { user_config.run_panel, { 'table', 'nil' }, true },
       diff = { user_config.diff, { 'table', 'nil' }, true },
     })
 
@@ -132,31 +130,24 @@ function M.setup(user_config)
       })
     end
 
-    if user_config.test_panel then
+    if user_config.run_panel then
       vim.validate({
         diff_mode = {
-          user_config.test_panel.diff_mode,
+          user_config.run_panel.diff_mode,
           function(value)
             return vim.tbl_contains({ 'vim', 'git' }, value)
           end,
           "diff_mode must be 'vim' or 'git'",
         },
-        toggle_key = {
-          user_config.test_panel.toggle_key,
-          function(value)
-            return type(value) == 'string' and value ~= ''
-          end,
-          'toggle_key must be a non-empty string',
-        },
         next_test_key = {
-          user_config.test_panel.next_test_key,
+          user_config.run_panel.next_test_key,
           function(value)
             return type(value) == 'string' and value ~= ''
           end,
           'next_test_key must be a non-empty string',
         },
         prev_test_key = {
-          user_config.test_panel.prev_test_key,
+          user_config.run_panel.prev_test_key,
           function(value)
             return type(value) == 'string' and value ~= ''
           end,
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index a27af41..2e9927b 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -25,7 +25,7 @@ local state = {
   saved_session = nil,
   test_cases = nil,
   test_states = {},
-  test_panel_active = false,
+  run_panel_active = false,
 }
 
 local constants = require('cp.constants')
@@ -149,14 +149,14 @@ local function get_current_problem()
   return filename
 end
 
-local function toggle_test_panel(is_debug)
-  if state.test_panel_active then
+local function toggle_run_panel(is_debug)
+  if state.run_panel_active then
     if state.saved_session then
       vim.cmd(('source %s'):format(state.saved_session))
       vim.fn.delete(state.saved_session)
       state.saved_session = nil
     end
-    state.test_panel_active = false
+    state.run_panel_active = false
     logger.log('test panel closed')
     return
   end
@@ -249,7 +249,7 @@ local function toggle_test_panel(is_debug)
   end
 
   local function update_expected_pane()
-    local test_state = test_module.get_test_panel_state()
+    local test_state = test_module.get_run_panel_state()
     local current_test = test_state.test_cases[test_state.current_index]
 
     if not current_test then
@@ -262,7 +262,7 @@ local function toggle_test_panel(is_debug)
     update_buffer_content(test_buffers.expected_buf, expected_lines, {})
 
     local diff_backend = require('cp.diff')
-    local backend = diff_backend.get_best_backend(config.test_panel.diff_mode)
+    local backend = diff_backend.get_best_backend(config.run_panel.diff_mode)
 
     if backend.name == 'vim' and current_test.status == 'fail' then
       vim.api.nvim_set_option_value('diff', true, { win = test_windows.expected_win })
@@ -272,7 +272,7 @@ local function toggle_test_panel(is_debug)
   end
 
   local function update_actual_pane()
-    local test_state = test_module.get_test_panel_state()
+    local test_state = test_module.get_run_panel_state()
     local current_test = test_state.test_cases[test_state.current_index]
 
     if not current_test then
@@ -291,7 +291,7 @@ local function toggle_test_panel(is_debug)
 
     if enable_diff then
       local diff_backend = require('cp.diff')
-      local backend = diff_backend.get_best_backend(config.test_panel.diff_mode)
+      local backend = diff_backend.get_best_backend(config.run_panel.diff_mode)
 
       if backend.name == 'git' then
         local diff_result = backend.render(current_test.expected, current_test.actual)
@@ -321,14 +321,14 @@ local function toggle_test_panel(is_debug)
     end
   end
 
-  local function refresh_test_panel()
+  local function refresh_run_panel()
     if not test_buffers.tab_buf or not vim.api.nvim_buf_is_valid(test_buffers.tab_buf) then
       return
     end
 
     local test_render = require('cp.test_render')
     test_render.setup_highlights()
-    local test_state = test_module.get_test_panel_state()
+    local test_state = test_module.get_run_panel_state()
     local tab_lines, tab_highlights = test_render.render_test_list(test_state)
     update_buffer_content(test_buffers.tab_buf, tab_lines, tab_highlights)
 
@@ -337,7 +337,7 @@ local function toggle_test_panel(is_debug)
   end
 
   local function navigate_test_case(delta)
-    local test_state = test_module.get_test_panel_state()
+    local test_state = test_module.get_run_panel_state()
     if #test_state.test_cases == 0 then
       return
     end
@@ -349,22 +349,19 @@ local function toggle_test_panel(is_debug)
       test_state.current_index = 1
     end
 
-    refresh_test_panel()
+    refresh_run_panel()
   end
 
-  vim.keymap.set('n', config.test_panel.next_test_key, function()
+  vim.keymap.set('n', config.run_panel.next_test_key, function()
     navigate_test_case(1)
   end, { buffer = test_buffers.tab_buf, silent = true })
-  vim.keymap.set('n', config.test_panel.prev_test_key, function()
+  vim.keymap.set('n', config.run_panel.prev_test_key, function()
     navigate_test_case(-1)
   end, { buffer = test_buffers.tab_buf, silent = true })
 
   for _, buf in pairs(test_buffers) do
     vim.keymap.set('n', 'q', function()
-      toggle_test_panel()
-    end, { buffer = buf, silent = true })
-    vim.keymap.set('n', config.test_panel.toggle_key, function()
-      toggle_test_panel()
+      toggle_run_panel()
     end, { buffer = buf, silent = true })
   end
 
@@ -382,14 +379,14 @@ local function toggle_test_panel(is_debug)
     test_module.run_all_test_cases(ctx, contest_config)
   end
 
-  refresh_test_panel()
+  refresh_run_panel()
 
   vim.api.nvim_set_current_win(test_windows.tab_win)
 
-  state.test_panel_active = true
+  state.run_panel_active = true
   state.test_buffers = test_buffers
   state.test_windows = test_windows
-  local test_state = test_module.get_test_panel_state()
+  local test_state = test_module.get_run_panel_state()
   logger.log(string.format('test panel opened (%d test cases)', #test_state.test_cases))
 end
 
@@ -556,8 +553,8 @@ function M.handle_command(opts)
   end
 
   if cmd.type == 'action' then
-    if cmd.action == 'test' then
-      toggle_test_panel(cmd.debug)
+    if cmd.action == 'run' then
+      toggle_run_panel(cmd.debug)
     elseif cmd.action == 'next' then
       navigate_problem(1, cmd.language)
     elseif cmd.action == 'prev' then
diff --git a/lua/cp/test.lua b/lua/cp/test.lua
index e4719e6..329f03c 100644
--- a/lua/cp/test.lua
+++ b/lua/cp/test.lua
@@ -12,7 +12,7 @@
 ---@field signal string?
 ---@field timed_out boolean?
 
----@class TestPanelState
+---@class RunPanelState
 ---@field test_cases TestCase[]
 ---@field current_index number
 ---@field buffer number?
@@ -24,8 +24,8 @@ local M = {}
 local constants = require('cp.constants')
 local logger = require('cp.log')
 
----@type TestPanelState
-local test_panel_state = {
+---@type RunPanelState
+local run_panel_state = {
   test_cases = {},
   current_index = 1,
   buffer = nil,
@@ -227,8 +227,8 @@ function M.load_test_cases(ctx, state)
     test_cases = parse_test_cases_from_files(ctx.input_file, ctx.expected_file)
   end
 
-  test_panel_state.test_cases = test_cases
-  test_panel_state.current_index = 1
+  run_panel_state.test_cases = test_cases
+  run_panel_state.current_index = 1
 
   logger.log(('loaded %d test case(s)'):format(#test_cases))
   return #test_cases > 0
@@ -239,7 +239,7 @@ end
 ---@param index number
 ---@return boolean
 function M.run_test_case(ctx, contest_config, index)
-  local test_case = test_panel_state.test_cases[index]
+  local test_case = run_panel_state.test_cases[index]
   if not test_case then
     return false
   end
@@ -266,16 +266,16 @@ end
 ---@return TestCase[]
 function M.run_all_test_cases(ctx, contest_config)
   local results = {}
-  for i, _ in ipairs(test_panel_state.test_cases) do
+  for i, _ in ipairs(run_panel_state.test_cases) do
     M.run_test_case(ctx, contest_config, i)
-    table.insert(results, test_panel_state.test_cases[i])
+    table.insert(results, run_panel_state.test_cases[i])
   end
   return results
 end
 
----@return TestPanelState
-function M.get_test_panel_state()
-  return test_panel_state
+---@return RunPanelState
+function M.get_run_panel_state()
+  return run_panel_state
 end
 
 return M
diff --git a/lua/cp/test_render.lua b/lua/cp/test_render.lua
index fad2836..9bbe699 100644
--- a/lua/cp/test_render.lua
+++ b/lua/cp/test_render.lua
@@ -201,7 +201,7 @@ local function data_row(c, idx, tc, is_current)
   return line, hi
 end
 
----@param test_state TestPanelState
+---@param test_state RunPanelState
 ---@return string[], table[] lines and highlight positions
 function M.render_test_list(test_state)
   local lines, highlights = {}, {}
diff --git a/spec/command_parsing_spec.lua b/spec/command_parsing_spec.lua
index ddeaca1..b66927a 100644
--- a/spec/command_parsing_spec.lua
+++ b/spec/command_parsing_spec.lua
@@ -51,7 +51,7 @@ describe('cp command parsing', function()
 
   describe('action commands', function()
     it('handles test action without error', function()
-      local opts = { fargs = { 'test' } }
+      local opts = { fargs = { 'run' } }
 
       assert.has_no_errors(function()
         cp.handle_command(opts)
@@ -126,7 +126,7 @@ describe('cp command parsing', function()
 
   describe('language flag parsing', function()
     it('logs error for --lang flag missing value', function()
-      local opts = { fargs = { 'test', '--lang' } }
+      local opts = { fargs = { 'run', '--lang' } }
 
       cp.handle_command(opts)
 
@@ -169,7 +169,7 @@ describe('cp command parsing', function()
 
   describe('debug flag parsing', function()
     it('handles debug flag without error', function()
-      local opts = { fargs = { 'test', '--debug' } }
+      local opts = { fargs = { 'run', '--debug' } }
 
       assert.has_no_errors(function()
         cp.handle_command(opts)
@@ -177,7 +177,7 @@ describe('cp command parsing', function()
     end)
 
     it('handles combined language and debug flags', function()
-      local opts = { fargs = { 'test', '--lang=cpp', '--debug' } }
+      local opts = { fargs = { 'run', '--lang=cpp', '--debug' } }
 
       assert.has_no_errors(function()
         cp.handle_command(opts)
@@ -234,7 +234,7 @@ describe('cp command parsing', function()
     end)
 
     it('handles flag order variations', function()
-      local opts = { fargs = { '--debug', 'test', '--lang=python' } }
+      local opts = { fargs = { '--debug', 'run', '--lang=python' } }
 
       assert.has_no_errors(function()
         cp.handle_command(opts)
@@ -242,7 +242,7 @@ describe('cp command parsing', function()
     end)
 
     it('handles multiple language flags', function()
-      local opts = { fargs = { 'test', '--lang=cpp', '--lang=python' } }
+      local opts = { fargs = { 'run', '--lang=cpp', '--lang=python' } }
 
       assert.has_no_errors(function()
         cp.handle_command(opts)
diff --git a/spec/config_spec.lua b/spec/config_spec.lua
index a429ae5..f05c07a 100644
--- a/spec/config_spec.lua
+++ b/spec/config_spec.lua
@@ -74,20 +74,10 @@ describe('cp.config', function()
       end)
     end)
 
-    describe('test_panel config validation', function()
+    describe('run_panel config validation', function()
       it('validates diff_mode values', function()
         local invalid_config = {
-          test_panel = { diff_mode = 'invalid' },
-        }
-
-        assert.has_error(function()
-          config.setup(invalid_config)
-        end)
-      end)
-
-      it('validates toggle_key is non-empty string', function()
-        local invalid_config = {
-          test_panel = { toggle_key = '' },
+          run_panel = { diff_mode = 'invalid' },
         }
 
         assert.has_error(function()
@@ -97,7 +87,7 @@ describe('cp.config', function()
 
       it('validates next_test_key is non-empty string', function()
         local invalid_config = {
-          test_panel = { next_test_key = nil },
+          run_panel = { next_test_key = nil },
         }
 
         assert.has_error(function()
@@ -107,7 +97,7 @@ describe('cp.config', function()
 
       it('validates prev_test_key is non-empty string', function()
         local invalid_config = {
-          test_panel = { prev_test_key = '' },
+          run_panel = { prev_test_key = '' },
         }
 
         assert.has_error(function()
@@ -115,11 +105,10 @@ describe('cp.config', function()
         end)
       end)
 
-      it('accepts valid test_panel config', function()
+      it('accepts valid run_panel config', function()
         local valid_config = {
-          test_panel = {
+          run_panel = {
             diff_mode = 'git',
-            toggle_key = 'x',
             next_test_key = 'j',
             prev_test_key = 'k',
           },

From 5e412e341a111c76f4332cc4c42f29ae6b5d4f2f Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 18:54:43 -0400
Subject: [PATCH 25/31] fix(test): test -> run final change

---
 lua/cp/constants.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lua/cp/constants.lua b/lua/cp/constants.lua
index e6cdc95..acabc3c 100644
--- a/lua/cp/constants.lua
+++ b/lua/cp/constants.lua
@@ -1,7 +1,7 @@
 local M = {}
 
 M.PLATFORMS = { 'atcoder', 'codeforces', 'cses' }
-M.ACTIONS = { 'test', 'next', 'prev' }
+M.ACTIONS = { 'run', 'next', 'prev' }
 
 M.CPP = 'cpp'
 M.PYTHON = 'python'

From 99340e551b0d70c7d1082ed8f4d518c72f033535 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 19:11:40 -0400
Subject: [PATCH 26/31] fix: permit lowercase snippets

---
 README.md              |   9 --
 doc/cp.txt             |  60 ++++++-----
 lua/cp/config.lua      |   9 ++
 lua/cp/init.lua        | 220 +++++++++++++++++++++++++++--------------
 lua/cp/snippets.lua    |   8 +-
 spec/snippets_spec.lua |  42 ++++++++
 6 files changed, 234 insertions(+), 114 deletions(-)

diff --git a/README.md b/README.md
index 49ffb34..14b5fe9 100644
--- a/README.md
+++ b/README.md
@@ -63,12 +63,3 @@ follows:
 
 - [competitest.nvim](https://github.com/xeluxee/competitest.nvim)
 - [assistant.nvim](https://github.com/A7Lavinraj/assistant.nvim)
-
-## TODO
-
-- general `:CP test` window improvements
-- fzf/telescope integration (whichever available)
-- finer-tuned problem limits (i.e. per-problem codeforces time, memory)
-- notify discord members
-- handle infinite output/trimming file to 500 lines (customizable)
-- update barrettruth.com to post
diff --git a/doc/cp.txt b/doc/cp.txt
index 8229fbf..3933a70 100644
--- a/doc/cp.txt
+++ b/doc/cp.txt
@@ -67,7 +67,7 @@ CONFIGURATION                                       *cp-config*
 
 cp.nvim works out of the box. No setup required.
 
-Optional configuration with lazy.nvim: >
+Here's an example configuration with lazy.nvim: >
     {
         'barrett-ruth/cp.nvim',
         cmd = 'CP',
@@ -75,7 +75,7 @@ Optional configuration with lazy.nvim: >
           debug = false,
           scrapers = {
             atcoder = true,
-            codeforces = false,  -- disable codeforces scraping
+            codeforces = false,
             cses = true,
           },
           contests = {
@@ -113,9 +113,10 @@ Optional configuration with lazy.nvim: >
             end,
           },
           run_panel = {
-            diff_mode = "vim",         -- "vim" or "git"
-            next_test_key = "<c-n>",   -- navigate to next test case
-            prev_test_key = "<c-p>",   -- navigate to previous test case
+            diff_mode = "vim",
+            next_test_key = "<c-n>",
+            prev_test_key = "<c-p>",
+            toggle_diff_key = "t",
           },
           diff = {
             git = {
@@ -175,6 +176,7 @@ Optional configuration with lazy.nvim: >
                         Git provides character-level precision, vim uses built-in diff.
       • {next_test_key} (`string`, default: `"<c-n>"`) Key to navigate to next test case.
       • {prev_test_key} (`string`, default: `"<c-p>"`) Key to navigate to previous test case.
+      • {toggle_diff_key} (`string`, default: `"t"`) Key to toggle diff mode between vim and git.
 
 *cp.DiffConfig*
 
@@ -271,15 +273,19 @@ Example: Setting up and solving AtCoder contest ABC324
 
 3. Start with problem A: >
     :CP a
+
+   Or do both at once with:
+    :CP atcoder abc324 a
+
 <   This creates a.cc and scrapes test cases
 
 4. Code your solution, then test: >
-    :CP test
+    :CP run
 <   Navigate with j/k, run specific tests with <enter>
-    Exit test panel with q or :CP test when done
+    Exit test panel with q or :CP run when done
 
 5. If needed, debug with sanitizers: >
-    :CP test --debug
+    :CP run --debug
 <
 6. Move to next problem: >
     :CP next
@@ -287,10 +293,6 @@ Example: Setting up and solving AtCoder contest ABC324
 
 6. Continue solving problems with :CP next/:CP prev navigation
 7. Submit solutions on AtCoder website
-
-Example: Quick setup for single Codeforces problem >
-    :CP codeforces 1933 a       " One command setup
-    :CP test                    " Test immediately
 <
 
 RUN PANEL                                          *cp-run*
@@ -310,19 +312,21 @@ Activation ~
 
 Interface ~
 
-The run panel uses a redesigned two-pane layout for efficient comparison:
+The run panel uses a professional table layout with precise column alignment:
 (note that the diff is indeed highlighted, not the weird amalgamation of
 characters below) >
 
-    ┌─ Tests ─────────────────────┐ ┌─ Expected vs Actual ───────────────────────┐
-    │ AC  1. 12ms                 │ │                             45ms │ Exit: 0 │
-    │ WA  > 2. 45ms               │ ├────────────────────────────────────────────┤
-    │     5 3                     │ │                                            │
-    │                             │ │ 4[-2-]{+3+}                                │
-    │ AC  3. 9ms                  │ │ 100                                        │
-    │ RTE 4. 0ms                  │ │ hello w[-o-]r{+o+}ld                       │
-    │                             │ │                                            │
-    └─────────────────────────────┘ └────────────────────────────────────────────┘
+    ┌──────┬────────┬────────┬───────────┐ ┌─ Expected vs Actual ──────────────────┐
+    │  #   │ Status │  Time  │ Exit Code │ │ 45.70ms │ Exit: 0                    │
+    ├──────┼────────┼────────┼───────────┤ ├────────────────────────────────────────┤
+    │  1   │   AC   │12.00ms │     0     │ │                                        │
+    │ >2   │   WA   │45.70ms │     1     │ │ 4[-2-]{+3+}                           │
+    ├──────┴────────┴────────┴───────────┤ │ 100                                    │
+    │5 3                                 │ │ hello w[-o-]r{+o+}ld                   │
+    ├──────┬────────┬────────┬───────────┤ │                                        │
+    │  3   │   AC   │ 9.00ms │     0     │ └────────────────────────────────────────┘
+    │  4   │   RTE  │ 0.00ms │139 (SIGUSR2)│
+    └──────┴────────┴────────┴───────────┘
 <
 
 Status Indicators ~
@@ -338,7 +342,8 @@ Keymaps ~
                                                 *cp-test-keys*
 <c-n>                           Navigate to next test case (configurable via run_panel.next_test_key)
 <c-p>                           Navigate to previous test case (configurable via run_panel.prev_test_key)
-q                               Exit test panel (restore layout)
+t                               Toggle diff mode between vim and git (configurable via run_panel.toggle_diff_key)
+q                               Exit test panel and restore layout
 
 Diff Modes ~
 
@@ -365,8 +370,8 @@ cp.nvim creates the following file structure upon problem setup:
     build/
       {problem_id}.run              " Compiled binary
     io/
-      {problem_id}.cpin             " Test input
-      {problem_id}.cpout            " Program output
+      {problem_id}.n.cpin           " nth test input
+      {problem_id}.n.cpout          " nth program output
       {problem_id}.expected         " Expected output
 
 The plugin automatically manages this structure and navigation between problems
@@ -377,8 +382,9 @@ SNIPPETS                                        *cp-snippets*
 cp.nvim integrates with LuaSnip for automatic template expansion. Built-in
 snippets include basic C++ and Python templates for each contest type.
 
-Snippet trigger names must EXACTLY match platform names ("codeforces" for
-CodeForces, "cses" for CSES, etc.).
+Snippet trigger names must match the following format exactly:
+
+    cp.nvim/{platform}
 
 Custom snippets can be added via the `snippets` configuration field.
 
diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index 225aab7..2242fa2 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -35,6 +35,7 @@
 ---@field diff_mode "vim"|"git" Diff backend to use
 ---@field next_test_key string Key to navigate to next test case
 ---@field prev_test_key string Key to navigate to previous test case
+---@field toggle_diff_key string Key to toggle diff mode
 
 ---@class DiffGitConfig
 ---@field command string Git executable name
@@ -82,6 +83,7 @@ M.defaults = {
     diff_mode = 'vim',
     next_test_key = '<c-n>',
     prev_test_key = '<c-p>',
+    toggle_diff_key = 't',
   },
   diff = {
     git = {
@@ -153,6 +155,13 @@ function M.setup(user_config)
           end,
           'prev_test_key must be a non-empty string',
         },
+        toggle_diff_key = {
+          user_config.run_panel.toggle_diff_key,
+          function(value)
+            return type(value) == 'string' and value ~= ''
+          end,
+          'toggle_diff_key must be a non-empty string',
+        },
       })
     end
 
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 2e9927b..d4a212a 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -28,6 +28,9 @@ local state = {
   run_panel_active = false,
 }
 
+local current_diff_layout = nil
+local current_mode = nil
+
 local constants = require('cp.constants')
 local platforms = constants.PLATFORMS
 local actions = constants.ACTIONS
@@ -151,6 +154,11 @@ end
 
 local function toggle_run_panel(is_debug)
   if state.run_panel_active then
+    if current_diff_layout then
+      current_diff_layout.cleanup()
+      current_diff_layout = nil
+      current_mode = nil
+    end
     if state.saved_session then
       vim.cmd(('source %s'):format(state.saved_session))
       vim.fn.delete(state.saved_session)
@@ -187,41 +195,15 @@ local function toggle_run_panel(is_debug)
 
   vim.cmd('silent only')
 
-  local tab_buf = vim.api.nvim_create_buf(false, true)
-  local expected_buf = vim.api.nvim_create_buf(false, true)
-  local actual_buf = vim.api.nvim_create_buf(false, true)
-
-  -- Set buffer options
-  for _, buf in ipairs({ tab_buf, expected_buf, actual_buf }) do
-    vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
-    vim.api.nvim_set_option_value('readonly', true, { buf = buf })
-    vim.api.nvim_set_option_value('modifiable', false, { buf = buf })
-  end
-
+  local tab_buf = create_buffer_with_options()
   local main_win = vim.api.nvim_get_current_win()
   vim.api.nvim_win_set_buf(main_win, tab_buf)
-  vim.api.nvim_set_option_value('filetype', 'cptest', { buf = tab_buf })
-
-  vim.cmd.split()
-  vim.api.nvim_win_set_buf(0, actual_buf)
-  vim.api.nvim_set_option_value('filetype', 'cptest', { buf = actual_buf })
-
-  vim.cmd.vsplit()
-  vim.api.nvim_win_set_buf(0, expected_buf)
-  vim.api.nvim_set_option_value('filetype', 'cptest', { buf = expected_buf })
-
-  local expected_win = vim.fn.bufwinid(expected_buf)
-  local actual_win = vim.fn.bufwinid(actual_buf)
 
   local test_windows = {
     tab_win = main_win,
-    actual_win = actual_win,
-    expected_win = expected_win,
   }
   local test_buffers = {
     tab_buf = tab_buf,
-    expected_buf = expected_buf,
-    actual_buf = actual_buf,
   }
 
   local highlight = require('cp.highlight')
@@ -248,30 +230,93 @@ local function toggle_run_panel(is_debug)
     end
   end
 
-  local function update_expected_pane()
-    local test_state = test_module.get_run_panel_state()
-    local current_test = test_state.test_cases[test_state.current_index]
+  local function create_buffer_with_options()
+    local buf = vim.api.nvim_create_buf(false, true)
+    vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
+    vim.api.nvim_set_option_value('readonly', true, { buf = buf })
+    vim.api.nvim_set_option_value('modifiable', false, { buf = buf })
+    vim.api.nvim_set_option_value('filetype', 'cptest', { buf = buf })
+    return buf
+  end
 
-    if not current_test then
-      return
-    end
+  local function create_vim_diff_layout(parent_win, expected_content, actual_content)
+    local expected_buf = create_buffer_with_options()
+    local actual_buf = create_buffer_with_options()
 
-    local expected_text = current_test.expected
-    local expected_lines = vim.split(expected_text, '\n', { plain = true, trimempty = true })
+    vim.api.nvim_set_current_win(parent_win)
+    vim.cmd.split()
+    local actual_win = vim.api.nvim_get_current_win()
+    vim.api.nvim_win_set_buf(actual_win, actual_buf)
 
-    update_buffer_content(test_buffers.expected_buf, expected_lines, {})
+    vim.cmd.vsplit()
+    local expected_win = vim.api.nvim_get_current_win()
+    vim.api.nvim_win_set_buf(expected_win, expected_buf)
+
+    local expected_lines = vim.split(expected_content, '\n', { plain = true, trimempty = true })
+    local actual_lines = vim.split(actual_content, '\n', { plain = true, trimempty = true })
+
+    update_buffer_content(expected_buf, expected_lines, {})
+    update_buffer_content(actual_buf, actual_lines, {})
+
+    vim.api.nvim_set_option_value('diff', true, { win = expected_win })
+    vim.api.nvim_set_option_value('diff', true, { win = actual_win })
+    vim.api.nvim_win_call(expected_win, function()
+      vim.cmd.diffthis()
+    end)
+    vim.api.nvim_win_call(actual_win, function()
+      vim.cmd.diffthis()
+    end)
+
+    return {
+      buffers = { expected_buf, actual_buf },
+      windows = { expected_win, actual_win },
+      cleanup = function()
+        pcall(vim.api.nvim_win_close, expected_win, true)
+        pcall(vim.api.nvim_win_close, actual_win, true)
+        pcall(vim.api.nvim_buf_delete, expected_buf, { force = true })
+        pcall(vim.api.nvim_buf_delete, actual_buf, { force = true })
+      end,
+    }
+  end
+
+  local function create_git_diff_layout(parent_win, expected_content, actual_content)
+    local diff_buf = create_buffer_with_options()
+
+    vim.api.nvim_set_current_win(parent_win)
+    vim.cmd.split()
+    local diff_win = vim.api.nvim_get_current_win()
+    vim.api.nvim_win_set_buf(diff_win, diff_buf)
 
     local diff_backend = require('cp.diff')
-    local backend = diff_backend.get_best_backend(config.run_panel.diff_mode)
+    local backend = diff_backend.get_best_backend('git')
+    local diff_result = backend.render(expected_content, actual_content)
 
-    if backend.name == 'vim' and current_test.status == 'fail' then
-      vim.api.nvim_set_option_value('diff', true, { win = test_windows.expected_win })
+    if diff_result.raw_diff and diff_result.raw_diff ~= '' then
+      highlight.parse_and_apply_diff(diff_buf, diff_result.raw_diff, diff_namespace)
     else
-      vim.api.nvim_set_option_value('diff', false, { win = test_windows.expected_win })
+      local lines = vim.split(actual_content, '\n', { plain = true, trimempty = true })
+      update_buffer_content(diff_buf, lines, {})
+    end
+
+    return {
+      buffers = { diff_buf },
+      windows = { diff_win },
+      cleanup = function()
+        pcall(vim.api.nvim_win_close, diff_win, true)
+        pcall(vim.api.nvim_buf_delete, diff_buf, { force = true })
+      end,
+    }
+  end
+
+  local function create_diff_layout(mode, parent_win, expected_content, actual_content)
+    if mode == 'git' then
+      return create_git_diff_layout(parent_win, expected_content, actual_content)
+    else
+      return create_vim_diff_layout(parent_win, expected_content, actual_content)
     end
   end
 
-  local function update_actual_pane()
+  local function update_diff_panes()
     local test_state = test_module.get_run_panel_state()
     local current_test = test_state.test_cases[test_state.current_index]
 
@@ -279,45 +324,67 @@ local function toggle_run_panel(is_debug)
       return
     end
 
-    local actual_lines = {}
-    local enable_diff = false
+    local expected_content = current_test.expected or ''
+    local actual_content = current_test.actual or '(not run yet)'
+    local should_show_diff = current_test.status == 'fail' and current_test.actual
 
-    if current_test.actual then
-      actual_lines = vim.split(current_test.actual, '\n', { plain = true, trimempty = true })
-      enable_diff = current_test.status == 'fail'
-    else
-      actual_lines = { '(not run yet)' }
+    if not should_show_diff then
+      expected_content = expected_content
+      actual_content = actual_content
     end
 
-    if enable_diff then
-      local diff_backend = require('cp.diff')
-      local backend = diff_backend.get_best_backend(config.run_panel.diff_mode)
+    local desired_mode = should_show_diff and config.run_panel.diff_mode or 'vim'
+
+    if current_diff_layout and current_mode ~= desired_mode then
+      current_diff_layout.cleanup()
+      current_diff_layout = nil
+      current_mode = nil
+    end
+
+    if not current_diff_layout then
+      current_diff_layout =
+        create_diff_layout(desired_mode, main_win, expected_content, actual_content)
+      current_mode = desired_mode
+
+      for _, buf in ipairs(current_diff_layout.buffers) do
+        setup_keybindings_for_buffer(buf)
+      end
+    else
+      if desired_mode == 'git' then
+        local diff_backend = require('cp.diff')
+        local backend = diff_backend.get_best_backend('git')
+        local diff_result = backend.render(expected_content, actual_content)
 
-      if backend.name == 'git' then
-        local diff_result = backend.render(current_test.expected, current_test.actual)
         if diff_result.raw_diff and diff_result.raw_diff ~= '' then
           highlight.parse_and_apply_diff(
-            test_buffers.actual_buf,
+            current_diff_layout.buffers[1],
             diff_result.raw_diff,
             diff_namespace
           )
         else
-          update_buffer_content(test_buffers.actual_buf, actual_lines, {})
+          local lines = vim.split(actual_content, '\n', { plain = true, trimempty = true })
+          update_buffer_content(current_diff_layout.buffers[1], lines, {})
         end
       else
-        update_buffer_content(test_buffers.actual_buf, actual_lines, {})
-        vim.api.nvim_set_option_value('diff', true, { win = test_windows.actual_win })
-        vim.api.nvim_win_call(test_windows.expected_win, function()
-          vim.cmd.diffthis()
-        end)
-        vim.api.nvim_win_call(test_windows.actual_win, function()
-          vim.cmd.diffthis()
-        end)
+        local expected_lines = vim.split(expected_content, '\n', { plain = true, trimempty = true })
+        local actual_lines = vim.split(actual_content, '\n', { plain = true, trimempty = true })
+        update_buffer_content(current_diff_layout.buffers[1], expected_lines, {})
+        update_buffer_content(current_diff_layout.buffers[2], actual_lines, {})
+
+        if should_show_diff then
+          vim.api.nvim_set_option_value('diff', true, { win = current_diff_layout.windows[1] })
+          vim.api.nvim_set_option_value('diff', true, { win = current_diff_layout.windows[2] })
+          vim.api.nvim_win_call(current_diff_layout.windows[1], function()
+            vim.cmd.diffthis()
+          end)
+          vim.api.nvim_win_call(current_diff_layout.windows[2], function()
+            vim.cmd.diffthis()
+          end)
+        else
+          vim.api.nvim_set_option_value('diff', false, { win = current_diff_layout.windows[1] })
+          vim.api.nvim_set_option_value('diff', false, { win = current_diff_layout.windows[2] })
+        end
       end
-    else
-      update_buffer_content(test_buffers.actual_buf, actual_lines, {})
-      vim.api.nvim_set_option_value('diff', false, { win = test_windows.expected_win })
-      vim.api.nvim_set_option_value('diff', false, { win = test_windows.actual_win })
     end
   end
 
@@ -332,8 +399,7 @@ local function toggle_run_panel(is_debug)
     local tab_lines, tab_highlights = test_render.render_test_list(test_state)
     update_buffer_content(test_buffers.tab_buf, tab_lines, tab_highlights)
 
-    update_expected_pane()
-    update_actual_pane()
+    update_diff_panes()
   end
 
   local function navigate_test_case(delta)
@@ -352,6 +418,16 @@ local function toggle_run_panel(is_debug)
     refresh_run_panel()
   end
 
+  local function setup_keybindings_for_buffer(buf)
+    vim.keymap.set('n', 'q', function()
+      toggle_run_panel()
+    end, { buffer = buf, silent = true })
+    vim.keymap.set('n', config.run_panel.toggle_diff_key, function()
+      config.run_panel.diff_mode = config.run_panel.diff_mode == 'vim' and 'git' or 'vim'
+      refresh_run_panel()
+    end, { buffer = buf, silent = true })
+  end
+
   vim.keymap.set('n', config.run_panel.next_test_key, function()
     navigate_test_case(1)
   end, { buffer = test_buffers.tab_buf, silent = true })
@@ -359,11 +435,7 @@ local function toggle_run_panel(is_debug)
     navigate_test_case(-1)
   end, { buffer = test_buffers.tab_buf, silent = true })
 
-  for _, buf in pairs(test_buffers) do
-    vim.keymap.set('n', 'q', function()
-      toggle_run_panel()
-    end, { buffer = buf, silent = true })
-  end
+  setup_keybindings_for_buffer(test_buffers.tab_buf)
 
   if config.hooks and config.hooks.before_test then
     config.hooks.before_test(ctx)
diff --git a/lua/cp/snippets.lua b/lua/cp/snippets.lua
index b7b03ed..e0237c8 100644
--- a/lua/cp/snippets.lua
+++ b/lua/cp/snippets.lua
@@ -102,7 +102,7 @@ if __name__ == "__main__":
 
   local user_overrides = {}
   for _, snippet in ipairs(config.snippets or {}) do
-    user_overrides[snippet.trigger] = snippet
+    user_overrides[snippet.trigger:lower()] = snippet
   end
 
   for language, template_set in pairs(template_definitions) do
@@ -110,14 +110,14 @@ if __name__ == "__main__":
     local filetype = constants.canonical_filetypes[language]
 
     for contest, template in pairs(template_set) do
-      local prefixed_trigger = ('cp.nvim/%s.%s'):format(contest, language)
-      if not user_overrides[prefixed_trigger] then
+      local prefixed_trigger = ('cp.nvim/%s.%s'):format(contest:lower(), language)
+      if not user_overrides[prefixed_trigger:lower()] then
         table.insert(snippets, s(prefixed_trigger, fmt(template, { i(1) })))
       end
     end
 
     for trigger, snippet in pairs(user_overrides) do
-      local prefix_match = trigger:match('^cp%.nvim/[^.]+%.(.+)$')
+      local prefix_match = trigger:lower():match('^cp%.nvim/[^.]+%.(.+)$')
       if prefix_match == language then
         table.insert(snippets, snippet)
       end
diff --git a/spec/snippets_spec.lua b/spec/snippets_spec.lua
index bdddb56..861c102 100644
--- a/spec/snippets_spec.lua
+++ b/spec/snippets_spec.lua
@@ -211,5 +211,47 @@ describe('cp.snippets', function()
 
       assert.equals(1, codeforces_count)
     end)
+
+    it('handles case-insensitive snippet triggers', function()
+      local mixed_case_snippet = {
+        trigger = 'cp.nvim/CodeForces.cpp',
+        body = 'mixed case template',
+      }
+      local upper_case_snippet = {
+        trigger = 'cp.nvim/ATCODER.cpp',
+        body = 'upper case template',
+      }
+      local config = {
+        snippets = { mixed_case_snippet, upper_case_snippet },
+      }
+
+      snippets.setup(config)
+
+      local cpp_snippets = mock_luasnip.added.cpp or {}
+
+      local has_mixed_case = false
+      local has_upper_case = false
+      local default_codeforces_count = 0
+      local default_atcoder_count = 0
+
+      for _, snippet in ipairs(cpp_snippets) do
+        if snippet.trigger == 'cp.nvim/CodeForces.cpp' then
+          has_mixed_case = true
+          assert.equals('mixed case template', snippet.body)
+        elseif snippet.trigger == 'cp.nvim/ATCODER.cpp' then
+          has_upper_case = true
+          assert.equals('upper case template', snippet.body)
+        elseif snippet.trigger == 'cp.nvim/codeforces.cpp' then
+          default_codeforces_count = default_codeforces_count + 1
+        elseif snippet.trigger == 'cp.nvim/atcoder.cpp' then
+          default_atcoder_count = default_atcoder_count + 1
+        end
+      end
+
+      assert.is_true(has_mixed_case)
+      assert.is_true(has_upper_case)
+      assert.equals(0, default_codeforces_count, 'Default codeforces snippet should be overridden')
+      assert.equals(0, default_atcoder_count, 'Default atcoder snippet should be overridden')
+    end)
   end)
 end)

From 0b14c2bb8711242980e37415207535fb82d34a96 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 19:22:13 -0400
Subject: [PATCH 27/31] fix(ci): format

---
 lua/cp/highlight.lua | 80 +++++++++++++++++++++++---------------------
 lua/cp/init.lua      | 24 +++++++------
 2 files changed, 55 insertions(+), 49 deletions(-)

diff --git a/lua/cp/highlight.lua b/lua/cp/highlight.lua
index 1f10fac..8cf8bf4 100644
--- a/lua/cp/highlight.lua
+++ b/lua/cp/highlight.lua
@@ -14,44 +14,42 @@ local M = {}
 ---@param text string Raw git diff output line
 ---@return string cleaned_text, DiffHighlight[]
 local function parse_diff_line(text)
-  local cleaned_text = text
-  local offset = 0
+  local result_text = ''
+  local highlights = {}
+  local pos = 1
 
-  -- Pattern for removed text: [-removed text-]
-  for removed_text in text:gmatch('%[%-(.-)%-%]') do
-    local start_pos = text:find('%[%-' .. vim.pesc(removed_text) .. '%-%]', 1, false)
-    if start_pos then
-      cleaned_text = cleaned_text:gsub('%[%-' .. vim.pesc(removed_text) .. '%-%]', '', 1)
-    end
-  end
-
-  -- Reset for added text parsing on the cleaned text
-  local final_text = cleaned_text
-  local final_highlights = {}
-  offset = 0
-
-  -- Pattern for added text: {+added text+}
-  for added_text in cleaned_text:gmatch('{%+(.-)%+}') do
-    local start_pos = final_text:find('{%+' .. vim.pesc(added_text) .. '%+}', 1, false)
-    if start_pos then
-      -- Calculate position after previous highlights
-      local highlight_start = start_pos - offset - 1 -- 0-based for extmarks
-      local highlight_end = highlight_start + #added_text
-
-      table.insert(final_highlights, {
-        line = 0, -- Will be set by caller
+  while pos <= #text do
+    local removed_start, removed_end, removed_content = text:find('%[%-(.-)%-%]', pos)
+    if removed_start and removed_start == pos then
+      local highlight_start = #result_text
+      result_text = result_text .. removed_content
+      table.insert(highlights, {
+        line = 0,
         col_start = highlight_start,
-        col_end = highlight_end,
-        highlight_group = 'CpDiffAdded',
+        col_end = #result_text,
+        highlight_group = 'CpDiffRemoved',
       })
-
-      -- Remove the marker
-      final_text = final_text:gsub('{%+' .. vim.pesc(added_text) .. '%+}', added_text, 1)
-      offset = offset + 4 -- Length of {+ and +}
+      pos = removed_end + 1
+    else
+      local added_start, added_end, added_content = text:find('{%+(.-)%+}', pos)
+      if added_start and added_start == pos then
+        local highlight_start = #result_text
+        result_text = result_text .. added_content
+        table.insert(highlights, {
+          line = 0,
+          col_start = highlight_start,
+          col_end = #result_text,
+          highlight_group = 'CpDiffAdded',
+        })
+        pos = added_end + 1
+      else
+        result_text = result_text .. text:sub(pos, pos)
+        pos = pos + 1
+      end
     end
   end
 
-  return final_text, final_highlights
+  return result_text, highlights
 end
 
 ---Parse complete git diff output
@@ -97,16 +95,20 @@ function M.parse_git_diff(diff_output)
           table.insert(all_highlights, highlight)
         end
       elseif not line:match('^%-') and not line:match('^\\') then -- Skip removed lines and "\ No newline" messages
-        -- Unchanged line - remove leading space if present
+        -- Word-diff content line or unchanged line
         local clean_line = line:match('^%s') and line:sub(2) or line
         local parsed_line, line_highlights = parse_diff_line(clean_line)
-        table.insert(content_lines, parsed_line)
 
-        -- Set line numbers for any highlights (shouldn't be any for unchanged lines)
-        local line_num = #content_lines
-        for _, highlight in ipairs(line_highlights) do
-          highlight.line = line_num - 1 -- 0-based for extmarks
-          table.insert(all_highlights, highlight)
+        -- Only add non-empty lines
+        if parsed_line ~= '' then
+          table.insert(content_lines, parsed_line)
+
+          -- Set line numbers for highlights
+          local line_num = #content_lines
+          for _, highlight in ipairs(line_highlights) do
+            highlight.line = line_num - 1 -- 0-based for extmarks
+            table.insert(all_highlights, highlight)
+          end
         end
       end
     end
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index d4a212a..014bb76 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -152,6 +152,19 @@ local function get_current_problem()
   return filename
 end
 
+local function create_buffer_with_options(filetype)
+  local buf = vim.api.nvim_create_buf(false, true)
+  vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
+  vim.api.nvim_set_option_value('readonly', true, { buf = buf })
+  vim.api.nvim_set_option_value('modifiable', false, { buf = buf })
+  if filetype then
+    vim.api.nvim_set_option_value('filetype', filetype, { buf = buf })
+  end
+  return buf
+end
+
+local setup_keybindings_for_buffer
+
 local function toggle_run_panel(is_debug)
   if state.run_panel_active then
     if current_diff_layout then
@@ -230,15 +243,6 @@ local function toggle_run_panel(is_debug)
     end
   end
 
-  local function create_buffer_with_options()
-    local buf = vim.api.nvim_create_buf(false, true)
-    vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
-    vim.api.nvim_set_option_value('readonly', true, { buf = buf })
-    vim.api.nvim_set_option_value('modifiable', false, { buf = buf })
-    vim.api.nvim_set_option_value('filetype', 'cptest', { buf = buf })
-    return buf
-  end
-
   local function create_vim_diff_layout(parent_win, expected_content, actual_content)
     local expected_buf = create_buffer_with_options()
     local actual_buf = create_buffer_with_options()
@@ -418,7 +422,7 @@ local function toggle_run_panel(is_debug)
     refresh_run_panel()
   end
 
-  local function setup_keybindings_for_buffer(buf)
+  setup_keybindings_for_buffer = function(buf)
     vim.keymap.set('n', 'q', function()
       toggle_run_panel()
     end, { buffer = buf, silent = true })

From 5f1e6dff9c7b3673f02d73eafaa13bc5ed79b7a2 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 19:24:34 -0400
Subject: [PATCH 28/31] fix: set file types

---
 lua/cp/init.lua | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 014bb76..f0e3a63 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -211,6 +211,7 @@ local function toggle_run_panel(is_debug)
   local tab_buf = create_buffer_with_options()
   local main_win = vim.api.nvim_get_current_win()
   vim.api.nvim_win_set_buf(main_win, tab_buf)
+  vim.api.nvim_set_option_value('filetype', 'cptest', { buf = tab_buf })
 
   local test_windows = {
     tab_win = main_win,
@@ -256,6 +257,9 @@ local function toggle_run_panel(is_debug)
     local expected_win = vim.api.nvim_get_current_win()
     vim.api.nvim_win_set_buf(expected_win, expected_buf)
 
+    vim.api.nvim_set_option_value('filetype', 'cptest', { buf = expected_buf })
+    vim.api.nvim_set_option_value('filetype', 'cptest', { buf = actual_buf })
+
     local expected_lines = vim.split(expected_content, '\n', { plain = true, trimempty = true })
     local actual_lines = vim.split(actual_content, '\n', { plain = true, trimempty = true })
 
@@ -291,6 +295,8 @@ local function toggle_run_panel(is_debug)
     local diff_win = vim.api.nvim_get_current_win()
     vim.api.nvim_win_set_buf(diff_win, diff_buf)
 
+    vim.api.nvim_set_option_value('filetype', 'cptest', { buf = diff_buf })
+
     local diff_backend = require('cp.diff')
     local backend = diff_backend.get_best_backend('git')
     local diff_result = backend.render(expected_content, actual_content)

From 97c7161c2e0793ef7ddcd7f48b26c35f1ee33635 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 19:25:11 -0400
Subject: [PATCH 29/31] fix: set keybinds for every buffer

---
 lua/cp/init.lua | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index f0e3a63..c91815a 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -346,9 +346,21 @@ local function toggle_run_panel(is_debug)
     local desired_mode = should_show_diff and config.run_panel.diff_mode or 'vim'
 
     if current_diff_layout and current_mode ~= desired_mode then
+      local saved_pos = vim.api.nvim_win_get_cursor(0)
       current_diff_layout.cleanup()
       current_diff_layout = nil
       current_mode = nil
+
+      current_diff_layout =
+        create_diff_layout(desired_mode, main_win, expected_content, actual_content)
+      current_mode = desired_mode
+
+      for _, buf in ipairs(current_diff_layout.buffers) do
+        setup_keybindings_for_buffer(buf)
+      end
+
+      pcall(vim.api.nvim_win_set_cursor, 0, saved_pos)
+      return
     end
 
     if not current_diff_layout then

From b5b37074fb7c773b3f6305d09d030c74da849eb5 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 19:33:28 -0400
Subject: [PATCH 30/31] fix(ci): validate config after merge

---
 doc/cp.txt           |   4 +-
 lua/cp/config.lua    | 117 +++++++++++++++++++++----------------------
 lua/cp/init.lua      |   4 +-
 spec/config_spec.lua |   2 +-
 4 files changed, 61 insertions(+), 66 deletions(-)

diff --git a/doc/cp.txt b/doc/cp.txt
index 3933a70..64f4609 100644
--- a/doc/cp.txt
+++ b/doc/cp.txt
@@ -104,7 +104,7 @@ Here's an example configuration with lazy.nvim: >
             },
           },
           hooks = {
-            before_test = function(ctx) vim.cmd.w() end,
+            before_run = function(ctx) vim.cmd.w() end,
             before_debug = function(ctx) ... end,
             setup_code = function(ctx)
               vim.wo.foldmethod = "marker"
@@ -186,7 +186,7 @@ Here's an example configuration with lazy.nvim: >
 *cp.Hooks*
 
     Fields: ~
-      • {before_test}?  (`function`) Called before test panel opens.
+      • {before_run}?  (`function`) Called before test panel opens.
                         `function(ctx: ProblemContext)`
       • {before_debug}? (`function`) Called before debug compilation.
                         `function(ctx: ProblemContext)`
diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index 2242fa2..d92c267 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -27,7 +27,7 @@
 ---@field timeout_ms? number
 
 ---@class Hooks
----@field before_test? fun(ctx: ProblemContext)
+---@field before_run? fun(ctx: ProblemContext)
 ---@field before_debug? fun(ctx: ProblemContext)
 ---@field setup_code? fun(ctx: ProblemContext)
 
@@ -72,7 +72,7 @@ M.defaults = {
   contests = {},
   snippets = {},
   hooks = {
-    before_test = nil,
+    before_run = nil,
     before_debug = nil,
     setup_code = nil,
   },
@@ -112,65 +112,6 @@ function M.setup(user_config)
       diff = { user_config.diff, { 'table', 'nil' }, true },
     })
 
-    if user_config.hooks then
-      vim.validate({
-        before_test = {
-          user_config.hooks.before_test,
-          { 'function', 'nil' },
-          true,
-        },
-        before_debug = {
-          user_config.hooks.before_debug,
-          { 'function', 'nil' },
-          true,
-        },
-        setup_code = {
-          user_config.hooks.setup_code,
-          { 'function', 'nil' },
-          true,
-        },
-      })
-    end
-
-    if user_config.run_panel then
-      vim.validate({
-        diff_mode = {
-          user_config.run_panel.diff_mode,
-          function(value)
-            return vim.tbl_contains({ 'vim', 'git' }, value)
-          end,
-          "diff_mode must be 'vim' or 'git'",
-        },
-        next_test_key = {
-          user_config.run_panel.next_test_key,
-          function(value)
-            return type(value) == 'string' and value ~= ''
-          end,
-          'next_test_key must be a non-empty string',
-        },
-        prev_test_key = {
-          user_config.run_panel.prev_test_key,
-          function(value)
-            return type(value) == 'string' and value ~= ''
-          end,
-          'prev_test_key must be a non-empty string',
-        },
-        toggle_diff_key = {
-          user_config.run_panel.toggle_diff_key,
-          function(value)
-            return type(value) == 'string' and value ~= ''
-          end,
-          'toggle_diff_key must be a non-empty string',
-        },
-      })
-    end
-
-    if user_config.diff then
-      vim.validate({
-        git = { user_config.diff.git, { 'table', 'nil' }, true },
-      })
-    end
-
     if user_config.contests then
       for contest_name, contest_config in pairs(user_config.contests) do
         for lang_name, lang_config in pairs(contest_config) do
@@ -214,6 +155,60 @@ function M.setup(user_config)
 
   local config = vim.tbl_deep_extend('force', M.defaults, user_config or {})
 
+  -- Validate merged config values
+  vim.validate({
+    before_run = {
+      config.hooks.before_run,
+      { 'function', 'nil' },
+      true,
+    },
+    before_debug = {
+      config.hooks.before_debug,
+      { 'function', 'nil' },
+      true,
+    },
+    setup_code = {
+      config.hooks.setup_code,
+      { 'function', 'nil' },
+      true,
+    },
+  })
+
+  vim.validate({
+    diff_mode = {
+      config.run_panel.diff_mode,
+      function(value)
+        return vim.tbl_contains({ 'vim', 'git' }, value)
+      end,
+      "diff_mode must be 'vim' or 'git'",
+    },
+    next_test_key = {
+      config.run_panel.next_test_key,
+      function(value)
+        return type(value) == 'string' and value ~= ''
+      end,
+      'next_test_key must be a non-empty string',
+    },
+    prev_test_key = {
+      config.run_panel.prev_test_key,
+      function(value)
+        return type(value) == 'string' and value ~= ''
+      end,
+      'prev_test_key must be a non-empty string',
+    },
+    toggle_diff_key = {
+      config.run_panel.toggle_diff_key,
+      function(value)
+        return type(value) == 'string' and value ~= ''
+      end,
+      'toggle_diff_key must be a non-empty string',
+    },
+  })
+
+  vim.validate({
+    git = { config.diff.git, { 'table', 'nil' }, true },
+  })
+
   for _, contest_config in pairs(config.contests) do
     for lang_name, lang_config in pairs(contest_config) do
       if type(lang_config) == 'table' and not lang_config.extension then
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index c91815a..54b75e4 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -459,8 +459,8 @@ local function toggle_run_panel(is_debug)
 
   setup_keybindings_for_buffer(test_buffers.tab_buf)
 
-  if config.hooks and config.hooks.before_test then
-    config.hooks.before_test(ctx)
+  if config.hooks and config.hooks.before_run then
+    config.hooks.before_run(ctx)
   end
 
   if is_debug and config.hooks and config.hooks.before_debug then
diff --git a/spec/config_spec.lua b/spec/config_spec.lua
index f05c07a..cd5b058 100644
--- a/spec/config_spec.lua
+++ b/spec/config_spec.lua
@@ -66,7 +66,7 @@ describe('cp.config', function()
 
     it('validates hook functions', function()
       local invalid_config = {
-        hooks = { before_test = 'not_a_function' },
+        hooks = { before_run = 'not_a_function' },
       }
 
       assert.has_error(function()

From c7338d01d8b5acc7974002bc950cd04005948db2 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Fri, 19 Sep 2025 19:35:35 -0400
Subject: [PATCH 31/31] fix: proper config values

---
 spec/config_spec.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spec/config_spec.lua b/spec/config_spec.lua
index cd5b058..5b41617 100644
--- a/spec/config_spec.lua
+++ b/spec/config_spec.lua
@@ -87,7 +87,7 @@ describe('cp.config', function()
 
       it('validates next_test_key is non-empty string', function()
         local invalid_config = {
-          run_panel = { next_test_key = nil },
+          run_panel = { next_test_key = '' },
         }
 
         assert.has_error(function()