feat(test): real integration tests

spec/panel_spec.lua

@@ -0,0 +1,93 @@
+describe('Panel integration', function()
+  local cp
+  local state
+  local logged_messages
+
+  before_each(function()
+    logged_messages = {}
+    local mock_logger = {
+      log = function(msg, level)
+        table.insert(logged_messages, { msg = msg, level = level })
+      end,
+      set_config = function() end,
+    }
+    package.loaded['cp.log'] = mock_logger
+
+    -- Reset state completely
+    state = require('cp.state')
+    state.reset()
+
+    cp = require('cp')
+    cp.setup({
+      contests = {
+        codeforces = {
+          default_language = 'cpp',
+          cpp = { extension = 'cpp', test = { 'echo', 'test' } },
+        },
+      },
+      scrapers = { 'codeforces' },
+    })
+  end)
+
+  after_each(function()
+    package.loaded['cp.log'] = nil
+    if state then
+      state.reset()
+    end
+  end)
+
+  it('should handle run command with properly set contest context', function()
+    -- First set up a contest context
+    cp.handle_command({ fargs = { 'codeforces', '2146', 'b' } })
+
+    -- Verify state was set correctly
+    local context = cp.get_current_context()
+    assert.equals('codeforces', context.platform)
+    assert.equals('2146', context.contest_id)
+    assert.equals('b', context.problem_id)
+
+    -- Now try to run the panel - this should NOT crash with "contest_id: expected string, got nil"
+    assert.has_no_errors(function()
+      cp.handle_command({ fargs = { 'run' } })
+    end)
+
+    -- Should log panel opened or no test cases found, but NOT a validation error
+    local has_validation_error = false
+    for _, log_entry in ipairs(logged_messages) do
+      if
+        log_entry.level == vim.log.levels.ERROR
+        and log_entry.msg:match('expected string, got nil')
+      then
+        has_validation_error = true
+        break
+      end
+    end
+    assert.is_false(has_validation_error)
+  end)
+
+  it('should catch state module vs state object contract violations', function()
+    -- This test specifically verifies that runner functions receive the right data type
+    local run = require('cp.runner.run')
+    local problem = require('cp.problem')
+    local config = require('cp.config')
+
+    -- Set up state properly
+    state.set_platform('codeforces')
+    state.set_contest_id('2146')
+    state.set_problem_id('b')
+
+    -- Create a proper context
+    local ctx = problem.create_context('codeforces', '2146', 'b', config.defaults)
+
+    -- This should work - passing the state MODULE (not state data)
+    assert.has_no_errors(function()
+      run.load_test_cases(ctx, state)
+    end)
+
+    -- This would break if we passed state data instead of state module
+    local fake_state_data = { platform = 'codeforces', contest_id = '2146', problem_id = 'b' }
+    assert.has_errors(function()
+      run.load_test_cases(ctx, fake_state_data) -- This should fail because no get_* methods
+    end)
+  end)
+end)