Improve JavaScript test coverage (currently at 10.75%)

[VatsalSy]

Current State

The JavaScript test suite shows only 10.75% overall statement coverage, with several critical components completely untested. While the testing infrastructure is well-designed, the actual coverage needs significant improvement.

Test Coverage Breakdown

✅ Well-Tested Components (100% coverage)

• platform-utils.js - Platform detection utilities
• shortcut-key.js - Keyboard shortcut functionality

⚠️ Partially Tested Components

• command-data.js - 6.6% coverage (only 13 of 196 lines tested)
• fix-line-length.js - 55.68% coverage (scripts directory)
• teaching.js - 1.2% coverage (only 3 of 250 lines tested)

❌ Untested Components (0% coverage)

• command-palette.js - Core search/command functionality
• main.js - Main application logic

Strengths of Current Testing Approach

1. Well-structured testing patterns

   • Dual-file approach separating behavioral tests from implementation tests
   • Comprehensive browser API mocking in setup.js
   • Good test isolation with proper cleanup

2. Quality test infrastructure

   • Thorough DOM manipulation testing
   • Platform-specific behavior testing
   • Error scenario coverage

Areas Requiring Improvement

1. Critical UI Components

The command palette and main application logic have zero test coverage. These are core user-facing features that should be thoroughly tested.

2. Search Functionality

The command palette search functionality using Fuse.js needs comprehensive testing including:

• Search result accuracy
• Keyboard navigation
• Filter functionality
• Edge cases (empty results, special characters)

3. Theme Toggle System

While the infrastructure exists, the actual theme switching logic needs testing:

• Theme persistence
• Cross-page theme consistency
• Theme toggle UI interactions

4. Teaching Module

With only 1.2% coverage, the course sorting and filtering functionality remains largely untested.

Recommended Actions

1. Priority 1: Test Critical User Paths

   • Command palette opening/closing
   • Search functionality
   • Keyboard navigation
   • Theme switching

2. Priority 2: Increase Coverage of Partially Tested Files

   • Complete testing of command-data.js event handlers
   • Test remaining fix-line-length.js edge cases
   • Add tests for teaching.js course management

3. Priority 3: Add Integration Tests

   • Test complete user workflows
   • Test cross-component interactions
   • Add visual regression tests for theme switching

Target Coverage Goals

• Short-term (1 month): Achieve 50% overall coverage
• Medium-term (3 months): Achieve 70% overall coverage
• Long-term: Maintain 80%+ coverage with CI/CD enforcement

Benefits of Improved Coverage

1. Reduced regression risk during feature development
2. Faster debugging with comprehensive test cases
3. Better documentation through test examples
4. Increased confidence in deployments

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This issue was identified during test suite analysis. The current test infrastructure is solid, but needs expansion to cover critical user-facing functionality.