test: add comprehensive tests for mini.files selection handling

- Add tests for path extraction in get_visual_selection, get_cursor_position, and get_range_selection
- Add tests for send_at_mention_for_visual_selection path comparison logic
- Verify proper handling of various mini.files buffer path formats
- Test path mismatch detection and warning behavior

Author: jdurand

tests/unit/mini_files_selection_spec.lua

@@ -0,0 +1,237 @@
+-- luacheck: globals expect
+require("tests.busted_setup")
+
+describe("mini.files selection handling", function()
+  local selection
+  local mock_vim
+  local mock_logger
+  local mock_claudecode_main
+
+  local function setup_mocks()
+    -- Clear modules
+    package.loaded["claudecode.selection"] = nil
+    package.loaded["claudecode.logger"] = nil
+    package.loaded["claudecode"] = nil
+
+    -- Mock logger
+    mock_logger = {
+      debug = function() end,
+      warn = function() end,
+      error = function() end,
+    }
+    package.loaded["claudecode.logger"] = mock_logger
+
+    -- Mock main claudecode module
+    mock_claudecode_main = {
+      state = {
+        server = {
+          -- Mock server object
+        }
+      },
+      send_at_mention = function(file_path, start_line, end_line, source)
+        -- Mock successful at-mention sending
+        return true, nil
+      end
+    }
+    package.loaded["claudecode"] = mock_claudecode_main
+
+    -- Mock vim
+    mock_vim = {
+      api = {
+        nvim_get_current_buf = function()
+          return 42 -- Mock buffer ID
+        end,
+        nvim_buf_get_name = function(buf_id)
+          if buf_id == 42 then
+            return "minifiles://42//Users/test/project/test.lua"
+          end
+          return "/Users/test/project/test.lua"
+        end,
+        nvim_get_mode = function()
+          return { mode = "V" }
+        end,
+        nvim_win_get_cursor = function()
+          return { 1, 0 }
+        end,
+        nvim_buf_get_lines = function()
+          return { "line 1", "line 2", "line 3" }
+        end,
+      },
+      fn = {
+        getpos = function(mark)
+          if mark == "v" then
+            return { 0, 1, 1, 0 }
+          end
+          return { 0, 0, 0, 0 }
+        end,
+        visualmode = function()
+          return "V"
+        end,
+      },
+      loop = {
+        now = function()
+          return 1000
+        end,
+        new_timer = function()
+          return {
+            start = function() end,
+            stop = function() end,
+            close = function() end,
+          }
+        end,
+      },
+      schedule_wrap = function(fn)
+        return fn
+      end,
+      deepcopy = function(obj)
+        return obj
+      end,
+    }
+
+    _G.vim = mock_vim
+  end
+
+  before_each(function()
+    setup_mocks()
+    selection = require("claudecode.selection")
+  end)
+
+  describe("get_visual_selection", function()
+    it("should extract filesystem path from mini.files buffer path", function()
+      -- Mock visual mode
+      mock_vim.api.nvim_get_mode = function()
+        return { mode = "V" }
+      end
+
+      local result = selection.get_visual_selection()
+
+      expect(result).to_be_table()
+      expect(result.filePath).to_be("/Users/test/project/test.lua")
+      expect(result.fileUrl).to_be("file:///Users/test/project/test.lua")
+      expect(result.text).to_be("line 1\nline 2\nline 3")
+    end)
+  end)
+
+  describe("get_cursor_position", function()
+    it("should extract filesystem path from mini.files buffer path", function()
+      local result = selection.get_cursor_position()
+
+      expect(result).to_be_table()
+      expect(result.filePath).to_be("/Users/test/project/test.lua")
+      expect(result.fileUrl).to_be("file:///Users/test/project/test.lua")
+      expect(result.text).to_be("")
+      expect(result.selection.isEmpty).to_be(true)
+    end)
+  end)
+
+  describe("get_range_selection", function()
+    it("should extract filesystem path from mini.files buffer path", function()
+      local result = selection.get_range_selection(1, 3)
+
+      expect(result).to_be_table()
+      expect(result.filePath).to_be("/Users/test/project/test.lua")
+      expect(result.fileUrl).to_be("file:///Users/test/project/test.lua")
+      expect(result.text).to_be("line 1\nline 2\nline 3")
+    end)
+  end)
+
+  describe("send_at_mention_for_visual_selection", function()
+    it("should handle path comparison with mini.files buffer paths", function()
+      -- Setup: latest selection has filesystem path, current buffer has mini.files path
+      selection.state.latest_selection = {
+        filePath = "/Users/test/project/test.lua",
+        text = "selected text",
+        selection = {
+          start = { line = 0, character = 0 },
+          ["end"] = { line = 2, character = 10 },
+          isEmpty = false
+        }
+      }
+      selection.state.tracking_enabled = true
+
+      local result = selection.send_at_mention_for_visual_selection()
+
+      expect(result).to_be(true)
+    end)
+
+    it("should warn when paths don't match after extraction", function()
+      -- Setup: selection path doesn't match current buffer path even after extraction
+      selection.state.latest_selection = {
+        filePath = "/Users/test/project/different_file.lua",
+        text = "selected text",
+        selection = {
+          start = { line = 0, character = 0 },
+          ["end"] = { line = 2, character = 10 },
+          isEmpty = false
+        }
+      }
+      selection.state.tracking_enabled = true
+
+      local warn_called = false
+      local warn_message = ""
+      mock_logger.warn = function(module, message)
+        warn_called = true
+        warn_message = message
+      end
+
+      local result = selection.send_at_mention_for_visual_selection()
+
+      expect(result).to_be(false)
+      expect(warn_called).to_be(true)
+      expect(warn_message).to_match("Tracked selection is for")
+      expect(warn_message).to_match("different_file.lua")
+      expect(warn_message).to_match("test.lua")
+    end)
+
+    it("should handle normal filesystem paths correctly", function()
+      -- Test with normal filesystem paths (not mini.files)
+      mock_vim.api.nvim_buf_get_name = function()
+        return "/Users/test/project/normal_file.lua"
+      end
+
+      selection.state.latest_selection = {
+        filePath = "/Users/test/project/normal_file.lua",
+        text = "selected text",
+        selection = {
+          start = { line = 0, character = 0 },
+          ["end"] = { line = 2, character = 10 },
+          isEmpty = false
+        }
+      }
+      selection.state.tracking_enabled = true
+
+      local result = selection.send_at_mention_for_visual_selection()
+
+      expect(result).to_be(true)
+    end)
+
+    it("should handle various mini.files path formats", function()
+      local test_cases = {
+        { buffer_path = "minifiles://42/Users/test/file.lua", expected = "Users/test/file.lua" },
+        { buffer_path = "minifiles://42//Users/test/file.lua", expected = "/Users/test/file.lua" },
+        { buffer_path = "minifiles://123///Users/test/file.lua", expected = "//Users/test/file.lua" },
+      }
+
+      for _, test_case in ipairs(test_cases) do
+        mock_vim.api.nvim_buf_get_name = function()
+          return test_case.buffer_path
+        end
+
+        selection.state.latest_selection = {
+          filePath = test_case.expected,
+          text = "selected text",
+          selection = {
+            start = { line = 0, character = 0 },
+            ["end"] = { line = 2, character = 10 },
+            isEmpty = false
+          }
+        }
+        selection.state.tracking_enabled = true
+
+        local result = selection.send_at_mention_for_visual_selection()
+
+        expect(result).to_be(true)
+      end
+    end)
+  end)
+end)