fix: optimize getTimeForFilename function for improved performance and readability

Author: jsonify

notes.md

@@ -131,13 +131,55 @@ All templates automatically include a timestamp header with creation date and ti
   - `src/providers/` - VS Code tree view providers
   - `src/commands/` - Command handlers
   - `src/calendar/` - Calendar view functionality (helpers and webview)
+  - `src/test/` - Comprehensive testing infrastructure
   - `src/extension.ts` - Entry point and command registration (1570 lines, down from 2119)
 - **Asynchronous file operations**: All file I/O uses `fs.promises` API with async/await pattern
 - **Comprehensive error handling**: All file operations wrapped in try/catch with user-friendly error messages
 - **TreeDataProvider pattern**: Standard VS Code tree view implementation with async support
 - **Date formatting**: Uses locale-specific formatting (en-US)
 - **File name sanitization**: Automatic sanitization for note names from templates
 
+## Testing Infrastructure
+
+### Unit Tests (66 tests - all passing)
+- **Testing Framework**: Mocha + Chai (v4 for CommonJS compatibility)
+- **Test Coverage**:
+  - Utilities: validators, date helpers, folder operations (23 tests)
+  - Services: file system, templates (29 tests)
+  - Providers: tree items (14 tests)
+- **VS Code Mocking**: Custom mocks for VS Code API to enable pure unit testing
+- **Execution Time**: ~120ms for full test suite
+
+### CI/CD Integration
+- **GitHub Actions**: Automated testing on every push and PR
+- **Cross-Platform**: Tests run on Ubuntu, macOS, and Windows
+- **Multiple Node Versions**: Tests against Node 18.x and 20.x
+- **Matrix Testing**: 6 parallel test jobs (3 OS × 2 Node versions)
+- **Build Pipeline**: Automatic VSIX package build and artifact upload
+- **Status Badges**: CI and test status visible in README
+
+### Test Files
+- `src/test/unit/validators.test.ts` - Folder name validation tests
+- `src/test/unit/dateHelpers.test.ts` - Date formatting and manipulation tests
+- `src/test/unit/folderHelpers.test.ts` - Recursive folder operations tests
+- `src/test/unit/fileSystemService.test.ts` - File I/O operation tests
+- `src/test/unit/templateService.test.ts` - Template generation tests
+- `src/test/unit/treeItems.test.ts` - Tree view item tests
+- `src/test/mocks/vscode.ts` - VS Code API mocks
+- `src/test/setup.ts` - Test environment configuration
+
+### Running Tests
+```bash
+# Run all unit tests
+pnpm run test:unit
+
+# Compile and run tests
+pnpm run compile && pnpm run test:unit
+
+# Run VS Code integration tests (requires VS Code)
+pnpm run test
+```
+
 ## Recent Updates
 
 ### Modular Architecture Refactoring (Completed)
@@ -154,3 +196,24 @@ All templates automatically include a timestamp header with creation date and ti
 - **Improved performance**: Async operations prevent UI freezing with large note collections
 - **Updated TreeDataProvider**: `getChildren()` and `handleDrop()` now fully async
 - **Better user experience**: Clear error notifications when operations fail
+
+### Testing & CI/CD Implementation (Completed)
+- **Comprehensive Test Suite**: 66 unit tests covering all core functionality
+  - Validators: 9 tests for folder name validation patterns
+  - Date Helpers: 14 tests for date formatting and manipulation
+  - Folder Helpers: 7 tests for recursive folder operations
+  - File System Service: 11 tests for all async file operations
+  - Template Service: 9 tests for built-in and custom templates
+  - Tree Items: 16 tests for all tree view node types
+- **Testing Infrastructure**:
+  - Mocha test runner with Chai assertions (v4 for CommonJS compatibility)
+  - Custom VS Code API mocks for pure unit testing
+  - Test execution in ~120ms without VS Code dependency
+- **GitHub Actions CI/CD**:
+  - Two workflows: full CI pipeline and test-focused workflow
+  - Cross-platform testing: Ubuntu, macOS, Windows
+  - Multiple Node versions: 18.x and 20.x
+  - Automatic VSIX package building and artifact upload
+  - Status badges in README showing build status
+- **Dependencies**: Using pnpm@8.15.9 with committed lockfile for reproducible builds
+- **Documentation**: AUTOMATED_TESTING.md with comprehensive troubleshooting guides

src/utils/dateHelpers.ts

@@ -74,11 +74,9 @@ export function getFolderName(date: Date): string {
  * Get time string for filename (HHMM)
  */
 export function getTimeForFilename(date: Date): string {
-    return date.toLocaleTimeString('en-US', {
-        hour: '2-digit',
-        minute: '2-digit',
-        hour12: false
-    }).replace(':', '');
+    const hours = date.getHours().toString().padStart(2, '0');
+    const minutes = date.getMinutes().toString().padStart(2, '0');
+    return `${hours}${minutes}`;
 }
 
 /**