refactor: organize tests and dry (#49)

* refactor(store): convert singleton to Store.new() factory

Problem: store.lua used module-level _data singleton, making
project-local stores impossible and creating hidden global state.

Solution: introduce Store metatable with all operations as instance
methods. M.new(path) constructs an instance; M.resolve_path()
searches upward for .pending.json and falls back to
config.get().data_path. Singleton module API is removed.

* refactor(diff): accept store instance as parameter

Problem: diff.apply called store singleton methods directly, coupling
it to global state and preventing use with project-local stores.

Solution: change signature to apply(lines, s, hidden_ids?) where s is
a pending.Store instance. All store operations now go through s.

* refactor(buffer): add set_store/store accessors, drop singleton dep

Problem: buffer.lua imported store directly and called singleton
methods, preventing it from working with per-project store instances.

Solution: add module-level _store, M.set_store(s), and M.store()
accessors. open() and render() use _store instead of the singleton.
init.lua will call buffer.set_store(s) before buffer.open().

* refactor(complete,health,sync,plugin): update callers to store instance API

Problem: complete.lua, health.lua, sync/gcal.lua, and plugin/pending.lua
all called singleton store methods directly.

Solution: complete.lua uses buffer.store() for category lookups;
health.lua uses store.new(store.resolve_path()) and reports the
resolved path; gcal.lua calls require('pending').store() for task
access; plugin tab-completion creates ephemeral store instances via
store.new(store.resolve_path()). Add 'init' to the subcommands list.

* feat(init): thread Store instance through init, add :Pending init

Problem: init.lua called singleton store methods throughout, and there
was no way to create a project-local .pending.json file.

Solution: add module-level _store and private get_store() that
lazy-constructs via store.new(store.resolve_path()). Add public
M.store() accessor used by specs and sync backends. M.open() calls
buffer.set_store(get_store()) before buffer.open(). All store
callsites converted to get_store():method(). goto_file() and
add_here() derive the data directory from get_store().path.

Add M.init() which creates .pending.json in cwd and dispatches from
M.command() as ':Pending init'.

* test: update all specs for Store instance API

Problem: every spec used the old singleton API (store.unload(),
store.load(), store.add(), etc.) and diff.apply(lines, hidden).

Solution: lower-level specs (store, diff, views, complete, file) use
s = store.new(path); s:load() directly. Higher-level specs (archive,
edit, filter, status, sync) reset package.loaded['pending'] in
before_each and use pending.store() to access the live instance.
diff.apply calls updated to diff.apply(lines, s, hidden_ids).

* docs(pending): document :Pending init and store resolution

Add *pending-store-resolution* section explaining upward .pending.json
discovery and fallback to the global data_path. Document :Pending init
under COMMANDS. Add a cross-reference from the data_path config field.

* ci: format

* ci: remove unused variable

lua/pending/store.lua

@@ -21,14 +21,17 @@ local config = require('pending.config')
 ---@field tasks pending.Task[]
 ---@field undo pending.Task[][]
 
+---@class pending.Store
+---@field path string
+---@field _data pending.Data?
+local Store = {}
+Store.__index = Store
+
 ---@class pending.store
 local M = {}
 
 local SUPPORTED_VERSION = 1
 
----@type pending.Data?
-local _data = nil
-
 ---@return pending.Data
 local function empty_data()
   return {
@@ -137,18 +140,18 @@ local function table_to_task(t)
 end
 
 ---@return pending.Data
-function M.load()
-  local path = config.get().data_path
+function Store:load()
+  local path = self.path
   local f = io.open(path, 'r')
   if not f then
-    _data = empty_data()
-    return _data
+    self._data = empty_data()
+    return self._data
   end
   local content = f:read('*a')
   f:close()
   if content == '' then
-    _data = empty_data()
-    return _data
+    self._data = empty_data()
+    return self._data
   end
   local ok, decoded = pcall(vim.json.decode, content)
   if not ok then
@@ -163,14 +166,14 @@ function M.load()
         .. '. Please update the plugin.'
     )
   end
-  _data = {
+  self._data = {
     version = decoded.version or SUPPORTED_VERSION,
     next_id = decoded.next_id or 1,
     tasks = {},
     undo = {},
   }
   for _, t in ipairs(decoded.tasks or {}) do
-    table.insert(_data.tasks, table_to_task(t))
+    table.insert(self._data.tasks, table_to_task(t))
   end
   for _, snapshot in ipairs(decoded.undo or {}) do
     if type(snapshot) == 'table' then
@@ -178,29 +181,29 @@ function M.load()
       for _, raw in ipairs(snapshot) do
         table.insert(tasks, table_to_task(raw))
       end
-      table.insert(_data.undo, tasks)
+      table.insert(self._data.undo, tasks)
     end
   end
-  return _data
+  return self._data
 end
 
 ---@return nil
-function M.save()
-  if not _data then
+function Store:save()
+  if not self._data then
     return
   end
-  local path = config.get().data_path
+  local path = self.path
   ensure_dir(path)
   local out = {
-    version = _data.version,
-    next_id = _data.next_id,
+    version = self._data.version,
+    next_id = self._data.next_id,
     tasks = {},
     undo = {},
   }
-  for _, task in ipairs(_data.tasks) do
+  for _, task in ipairs(self._data.tasks) do
     table.insert(out.tasks, task_to_table(task))
   end
-  for _, snapshot in ipairs(_data.undo) do
+  for _, snapshot in ipairs(self._data.undo) do
     local serialized = {}
     for _, task in ipairs(snapshot) do
       table.insert(serialized, task_to_table(task))
@@ -223,22 +226,22 @@ function M.save()
 end
 
 ---@return pending.Data
-function M.data()
-  if not _data then
-    M.load()
+function Store:data()
+  if not self._data then
+    self:load()
   end
-  return _data --[[@as pending.Data]]
+  return self._data --[[@as pending.Data]]
 end
 
 ---@return pending.Task[]
-function M.tasks()
-  return M.data().tasks
+function Store:tasks()
+  return self:data().tasks
 end
 
 ---@return pending.Task[]
-function M.active_tasks()
+function Store:active_tasks()
   local result = {}
-  for _, task in ipairs(M.tasks()) do
+  for _, task in ipairs(self:tasks()) do
     if task.status ~= 'deleted' then
       table.insert(result, task)
     end
@@ -248,8 +251,8 @@ end
 
 ---@param id integer
 ---@return pending.Task?
-function M.get(id)
-  for _, task in ipairs(M.tasks()) do
+function Store:get(id)
+  for _, task in ipairs(self:tasks()) do
     if task.id == id then
       return task
     end
@@ -259,8 +262,8 @@ end
 
 ---@param fields { description: string, status?: string, category?: string, priority?: integer, due?: string, recur?: string, recur_mode?: string, order?: integer, _extra?: table }
 ---@return pending.Task
-function M.add(fields)
-  local data = M.data()
+function Store:add(fields)
+  local data = self:data()
   local now = timestamp()
   local task = {
     id = data.next_id,
@@ -285,8 +288,8 @@ end
 ---@param id integer
 ---@param fields table<string, any>
 ---@return pending.Task?
-function M.update(id, fields)
-  local task = M.get(id)
+function Store:update(id, fields)
+  local task = self:get(id)
   if not task then
     return nil
   end
@@ -309,14 +312,14 @@ end
 
 ---@param id integer
 ---@return pending.Task?
-function M.delete(id)
-  return M.update(id, { status = 'deleted', ['end'] = timestamp() })
+function Store:delete(id)
+  return self:update(id, { status = 'deleted', ['end'] = timestamp() })
 end
 
 ---@param id integer
 ---@return integer?
-function M.find_index(id)
-  for i, task in ipairs(M.tasks()) do
+function Store:find_index(id)
+  for i, task in ipairs(self:tasks()) do
     if task.id == id then
       return i
     end
@@ -326,14 +329,14 @@ end
 
 ---@param tasks pending.Task[]
 ---@return nil
-function M.replace_tasks(tasks)
-  M.data().tasks = tasks
+function Store:replace_tasks(tasks)
+  self:data().tasks = tasks
 end
 
 ---@return pending.Task[]
-function M.snapshot()
+function Store:snapshot()
   local result = {}
-  for _, task in ipairs(M.active_tasks()) do
+  for _, task in ipairs(self:active_tasks()) do
     local copy = {}
     for k, v in pairs(task) do
       if k ~= '_extra' then
@@ -352,25 +355,44 @@ function M.snapshot()
 end
 
 ---@return pending.Task[][]
-function M.undo_stack()
-  return M.data().undo
+function Store:undo_stack()
+  return self:data().undo
 end
 
 ---@param stack pending.Task[][]
 ---@return nil
-function M.set_undo_stack(stack)
-  M.data().undo = stack
+function Store:set_undo_stack(stack)
+  self:data().undo = stack
 end
 
 ---@param id integer
 ---@return nil
-function M.set_next_id(id)
-  M.data().next_id = id
+function Store:set_next_id(id)
+  self:data().next_id = id
 end
 
 ---@return nil
-function M.unload()
-  _data = nil
+function Store:unload()
+  self._data = nil
+end
+
+---@param path string
+---@return pending.Store
+function M.new(path)
+  return setmetatable({ path = path, _data = nil }, Store)
+end
+
+---@return string
+function M.resolve_path()
+  local results = vim.fs.find('.pending.json', {
+    upward = true,
+    path = vim.fn.getcwd(),
+    type = 'file',
+  })
+  if results and #results > 0 then
+    return results[1]
+  end
+  return config.get().data_path
 end
 
 return M