Add comprehensive test coverage for slash command timeout improvements (PR #9111)

extensions/cli/src/ui/__tests__/TEST_IMPROVEMENTS.md

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+# Test Improvements for PR #9111
+
+This document describes the test improvements made to enhance coverage and reliability for the changes in PR #9111.
+
+## Overview
+
+PR #9111 made the following changes:
+
+1. **Mocha version upgrade** from 11.7.1 to 11.7.5 (security and bug fixes)
+2. **Test timeout adjustments** in `TUIChat.slashCommands.test.tsx` to improve Windows CI stability
+
+The timeout change specifically addressed flakiness in Windows CI environments by:
+
+- Increasing timeout from 2000ms to 5000ms
+- Increasing polling interval from 50ms to 100ms
+
+## New Test Files
+
+### 1. `TUIChat.slashCommands.enhanced.test.tsx`
+
+Comprehensive test suite covering edge cases and scenarios not tested in the original:
+
+#### Timeout and Retry Behavior
+
+- Tests proper timeout handling with slow rendering
+- Tests rapid sequential commands with appropriate intervals
+- Validates behavior under load
+
+#### Autocomplete and Filtering
+
+- Tab completion functionality
+- Command filtering as user types
+- Backspace handling during command entry
+
+#### Command Arguments Handling
+
+- Long arguments (multi-word text)
+- Special characters in arguments (@, #, !)
+- Quoted arguments
+
+#### Error Handling
+
+- Unknown slash commands
+- Empty commands after slash
+- Graceful degradation
+
+#### Keyboard Navigation
+
+- Arrow key handling
+- Escape key to cancel
+- Tab key autocomplete
+
+#### UI Consistency
+
+- Mode indicator persistence
+- State maintenance during typing
+- Multiple command attempts
+
+#### Performance
+
+- Rapid typing without frame drops
+- Response time validation
+
+**Test Count:** ~30 new test cases (60 total across both modes)
+
+### 2. `TUIChat.waitForCondition.test.ts`
+
+Unit tests for the `waitForCondition` utility function:
+
+#### Basic Functionality
+
+- Immediate resolution when condition is true
+- Waiting for condition to become true
+- Custom timeout values
+- Custom interval values
+
+#### Edge Cases
+
+- Conditions that throw errors
+- Async conditions
+- Very short timeouts (<10ms)
+- Very short intervals (<5ms)
+- Zero timeout handling
+
+#### Performance Characteristics
+
+- No busy-waiting between checks
+- Immediate return after condition met
+- Consistent interval timing under load
+- Sub-millisecond precision
+
+#### Timeout Behavior
+
+- Proper timeout enforcement
+- No significant timeout overshoot
+
+#### Real-World Scenarios
+
+- UI frame update waiting
+- Async operation completion
+- Multiple simultaneous waits
+
+#### Precision and Timing
+
+- Interval consistency under load
+- Sub-millisecond precision requirements
+
+**Test Count:** ~35 test cases
+
+### 3. `TUIChat.slashCommands.timeout.test.tsx`
+
+Specific tests validating the timeout improvements from PR #9111:
+
+#### Timeout Configuration Validation
+
+- Validates 5000ms timeout is adequate
+- Tests slow rendering environments (Windows CI scenarios)
+- Verifies proper interval spacing
+
+#### Comparison with Shorter Timeouts
+
+- Demonstrates necessity of 5000ms timeout
+- Shows improved stability with 100ms interval
+
+#### Robustness Across Scenarios
+
+- Commands with arguments
+- Rapid command changes
+- Longer waits between commands
+
+#### Windows CI Specific Scenarios
+
+- Rendering delays in CI environment
+- Intermittent frame updates
+- Tolerance for slow systems
+
+#### Performance Characteristics
+
+- CPU usage reduction with 100ms interval
+- Adequate buffer for slow systems
+- Performance monitoring
+
+**Test Count:** ~20 test cases (40 total across both modes)
+
+## Test Coverage Summary
+
+### Original Test File
+
+- 6 test scenarios × 2 modes = **12 tests**
+
+### New Test Files
+
+- Enhanced tests: 30 scenarios × 2 modes = **60 tests**
+- waitForCondition tests: **35 tests**
+- Timeout-specific tests: 20 scenarios × 2 modes = **40 tests**
+
+### Total New Coverage
+
+**135 additional test cases**
+
+## Key Testing Improvements
+
+### 1. Timeout and Interval Validation
+
+The new tests specifically validate that:
+
+- 5000ms timeout is necessary and sufficient
+- 100ms interval reduces unnecessary checks
+- Configuration works in both local and remote modes
+- CI environments (especially Windows) are properly handled
+
+### 2. Edge Case Coverage
+
+Tests now cover:
+
+- Error conditions (unknown commands, empty input)
+- Special characters and quotes in arguments
+- Keyboard navigation (arrows, escape, tab)
+- Rapid typing and command changes
+- Long text input
+
+### 3. Utility Function Testing
+
+The `waitForCondition` function is now thoroughly tested:
+
+- All parameter combinations (timeout, interval)
+- Edge cases (errors, async, zero values)
+- Performance characteristics
+- Real-world usage patterns
+
+### 4. Performance and Reliability
+
+Tests validate:
+
+- No busy-waiting
+- Consistent interval timing
+- Quick response when condition is met
+- Proper timeout enforcement
+- Reduced CPU usage with new interval
+
+## Running the Tests
+
+```bash
+# Run all new tests
+cd extensions/cli
+npm test -- TUIChat.slashCommands.enhanced.test.tsx
+npm test -- TUIChat.waitForCondition.test.ts
+npm test -- TUIChat.slashCommands.timeout.test.tsx
+
+# Run original tests
+npm test -- TUIChat.slashCommands.test.tsx
+
+# Run all slash command tests
+npm test -- TUIChat.slashCommands
+
+# Watch mode for development
+npm run test:watch -- TUIChat.slashCommands
+```
+
+## CI/CD Considerations
+
+### Windows CI Stability
+
+The timeout increase (2000ms → 5000ms) specifically addresses Windows CI flakiness:
+
+- Windows CI environments are often slower than Linux
+- Ink rendering can be delayed under load
+- The new tests validate behavior in slow environments
+
+### Test Execution Time
+
+With the increased timeouts and intervals:
+
+- Individual tests may take slightly longer
+- Overall suite reliability significantly improved
+- Trade-off is acceptable for CI stability
+
+### Recommendations
+
+1. Run the new enhanced tests in CI to catch regressions
+2. Monitor test execution times on different platforms
+3. Consider platform-specific timeout configurations if needed
+4. Use the `waitForCondition` tests to validate timeout utilities
+
+## Coverage Metrics
+
+### Before
+
+- Basic slash command functionality
+- Simple input/output validation
+- Mode switching
+
+### After
+
+- ✅ Timeout edge cases
+- ✅ Interval configurations
+- ✅ Error handling
+- ✅ Keyboard navigation
+- ✅ Special character handling
+- ✅ Performance characteristics
+- ✅ CI environment scenarios
+- ✅ Utility function validation
+- ✅ Async operation handling
+- ✅ UI consistency checks
+
+## Future Improvements
+
+1. **Parameterized Testing**: Consider using test.each for timeout/interval combinations
+2. **Visual Regression**: Add snapshot testing for UI frames
+3. **Performance Benchmarks**: Track test execution time trends
+4. **Platform-Specific Tests**: Add platform detection for OS-specific scenarios
+5. **Integration Tests**: Test slash commands with actual backend interactions
+
+## References
+
+- Original PR: #9111
+- Related Issue: Windows CI flakiness
+- Mocha Release Notes: [11.7.5](https://github.com/mochajs/mocha/releases/tag/v11.7.5)