chess/planning/testing/testing-strategy.md

Chess Game Testing Strategy

Overview

This document outlines the comprehensive testing strategy for the HTML chess game implementation. The strategy follows a test pyramid approach, ensuring robust quality assurance at multiple levels.

Testing Philosophy

• Test-Driven Development (TDD): Write tests before implementation
• Continuous Integration: Automated test execution on every commit
• Quality Gates: Minimum coverage and performance thresholds
• Shift-Left Testing: Catch defects early in development

Testing Pyramid

           /\
          /E2E\          <- 10% (Critical user journeys)
         /------\
        /Integr.\        <- 20% (Component interactions)
       /----------\
      /    Unit    \     <- 70% (Individual functions/components)
     /--------------\

1. Unit Tests (70% of test suite)

Scope: Individual functions, classes, and components in isolation

Coverage Areas:

• Chess logic (piece movements, rules validation)
• Game state management
• UI component rendering
• Utility functions
• Helper methods

Tools:

• Jest for JavaScript testing
• JSDOM for DOM manipulation testing
• Mock objects for dependencies

Execution:

• Run on every file save (watch mode)
• Must pass before commit (pre-commit hook)
• Target: <50ms per test

2. Integration Tests (20% of test suite)

Scope: Multiple components working together

Coverage Areas:

• Board + pieces interaction
• Game engine + UI synchronization
• Move validation + state updates
• Event handling flows
• Data persistence + retrieval

Tools:

• Jest with integration test configuration
• Testing Library for component integration
• LocalStorage mocking

Execution:

• Run before push (pre-push hook)
• Target: <200ms per test

3. End-to-End Tests (10% of test suite)

Scope: Complete user workflows in real browser

Coverage Areas:

• Full game scenarios (opening to checkmate)
• User interactions (drag-drop, click-to-move)
• Visual feedback and animations
• Save/load game functionality
• Error handling and edge cases

Tools:

• Playwright for cross-browser testing
• Visual regression with Percy or Chromatic
• Accessibility testing with axe-core

Execution:

• Run in CI/CD pipeline
• Nightly runs for full browser matrix
• Target: <5s per test

Test Categories

A. Functional Testing

Chess Rules Validation

• Movement Rules: Each piece type follows correct patterns
• Capture Mechanics: Pieces capture opponent pieces correctly
• Special Moves: Castling, en passant, pawn promotion
• Game State: Check, checkmate, stalemate detection
• Illegal Moves: System prevents invalid moves

Game Flow

• Turn Management: Alternating white/black turns
• Move History: Track and display all moves
• Undo/Redo: Revert and reapply moves
• Time Controls: Clock management (if implemented)
• Game Termination: Resignation, timeout, draw offers

B. Non-Functional Testing

Performance

• Initial Load: <2 seconds to interactive
• Move Calculation: <100ms for legal move generation
• Rendering: 60 FPS during animations
• Memory: No leaks over extended gameplay

Usability

• Drag-and-Drop: Smooth piece movement
• Visual Feedback: Highlight valid moves, check state
• Responsive Design: Mobile, tablet, desktop layouts
• Keyboard Navigation: Accessible controls

Accessibility

• WCAG 2.1 AA: Screen reader support
• Keyboard Controls: Full functionality without mouse
• Color Contrast: Minimum 4.5:1 ratio
• Focus Management: Clear visual indicators

C. Cross-Browser Testing

Target Browsers:

• Chrome (latest, -1, -2)
• Firefox (latest, -1)
• Safari (latest, -1)
• Edge (latest)
• Mobile: iOS Safari, Chrome Android

Test Matrix:

• Desktop: Windows 10/11, macOS, Linux
• Mobile: iOS 15+, Android 10+

Test Data Management

Static Test Data

• Famous Positions: Fool's Mate, Scholar's Mate, Opera Game
• Edge Cases: Three-fold repetition, 50-move rule
• Endgames: King+Rook vs King, King+Queen vs King

Dynamic Test Data

• Generated Positions: Random legal board states
• PGN Files: Real games for replay testing
• FEN Strings: Specific test scenarios

Test Data Location

• /docs/testing/test-data/positions/ - FEN strings
• /docs/testing/test-data/games/ - PGN files
• /docs/testing/test-data/scenarios/ - JSON test cases

Quality Gates

Code Coverage Thresholds

{
  "statements": 85,
  "branches": 80,
  "functions": 85,
  "lines": 85
}

Performance Budgets

• Initial bundle size: <150KB (gzipped)
• Move calculation: <100ms
• UI update: <16ms (60 FPS)
• Memory usage: <50MB

Accessibility Standards

• WCAG 2.1 Level AA compliance
• No critical axe-core violations
• Keyboard navigation complete

CI/CD Integration

Pre-Commit

npm run lint
npm run test:unit
npm run typecheck

Pre-Push

npm run test:integration
npm run test:coverage

CI Pipeline

- Install dependencies
- Run linters
- Run unit tests
- Run integration tests
- Generate coverage report
- Run E2E tests (Chrome, Firefox)
- Visual regression tests
- Accessibility scan
- Performance audit

Nightly Build

• Full browser matrix E2E tests
• Extended performance testing
• Security vulnerability scan
• Dependency updates check

Test Maintenance

Test Review Criteria

• Each test has clear description
• Tests are independent and isolated
• No hardcoded values (use constants/fixtures)
• Proper setup and teardown
• Meaningful assertions

Flaky Test Management

• Retry failed tests (max 2 retries)
• Flag consistently flaky tests
• Weekly review and fix flaky tests
• Never skip tests permanently

Test Documentation

• Document complex test scenarios
• Maintain test data catalog
• Keep testing tools up to date
• Share testing best practices

Metrics and Reporting

Key Metrics

• Test Coverage: Overall and per-component
• Test Execution Time: Track trends
• Pass/Fail Rate: Monitor stability
• Bug Escape Rate: Production issues found

Dashboards

• Real-time test results in CI
• Coverage trends over time
• Performance benchmarks history
• Accessibility compliance score

Risk-Based Testing

Critical Paths (High Priority)

1. Legal move validation
2. Checkmate detection
3. Game state persistence
4. User input handling

Medium Priority

1. Move history display
2. Undo/redo functionality
3. Visual animations
4. Board rotation

Low Priority

1. Theme customization
2. Sound effects
3. Move suggestions
4. Game analysis

Testing Schedule

Sprint Activities

• Day 1-2: Write unit tests for new features
• Day 3-5: Implement features (TDD)
• Day 6-7: Integration testing
• Day 8: E2E test updates
• Day 9: Bug fixing
• Day 10: Release candidate testing

Tools and Frameworks

See testing-tools.md for detailed setup instructions.

Success Criteria

A feature is considered "done" when:

1. All tests pass (unit, integration, E2E)
2. Code coverage meets thresholds
3. Performance budgets are met
4. Accessibility scan passes
5. Code review approved
6. Documentation updated

References

• Test Specifications
• Quality Criteria
• Testing Tools
• Test Data Catalog