feat: add C# and Dart language support

commands/flutter-test.md

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+---
+description: Run Flutter/Dart tests, report failures, and incrementally fix test issues. Covers unit, widget, golden, and integration tests.
+---
+
+# Flutter Test
+
+This command runs the Flutter test suite and reports results. When failures occur, it diagnoses and fixes issues incrementally.
+
+## What This Command Does
+
+1. **Run Tests**: Execute `flutter test` (or scope to changed files)
+2. **Parse Failures**: Identify failing tests by type and cause
+3. **Fix Incrementally**: One failure at a time where possible
+4. **Verify**: Re-run after each fix
+5. **Report**: Show coverage summary and remaining failures
+
+## When to Use
+
+Use `/flutter-test` when:
+- After implementing a feature to verify nothing broke
+- After running `/flutter-build` to ensure tests pass
+- To check test coverage on new code
+- When a specific test file is failing
+- Before submitting a PR
+
+## Commands Run
+
+```bash
+# Run all tests
+flutter test 2>&1
+
+# Run with coverage
+flutter test --coverage 2>&1
+
+# Run specific test file
+flutter test test/unit/domain/usecases/get_user_test.dart 2>&1
+
+# Run tests matching a name pattern
+flutter test --name "CartBloc" 2>&1
+
+# Run integration tests (requires device/emulator)
+flutter test integration_test/ 2>&1
+
+# Update golden files when intentional visual changes are made
+flutter test --update-goldens 2>&1
+```
+
+## Example Session
+
+````text
+User: /flutter-test
+
+Agent:
+# Flutter Test Run
+
+## Test Execution
+
+```
+$ flutter test
+00:05 +42 -2: Some tests failed.
+
+FAILED: test/unit/data/user_repository_test.dart
+  UserRepository getById
+    returns null when user not found
+    Expected: null
+    Actual: User(id: 'test-id', name: 'Test User')
+
+FAILED: test/widget/cart_page_test.dart
+  CartPage
+    shows empty state when cart is empty
+    Expected: exactly one widget with text 'Your cart is empty'
+    Found: no widget with text 'Your cart is empty'
+```
+
+## Fix 1: Repository Test
+
+File: test/unit/data/user_repository_test.dart
+Failure: `getById` returns a user when it should return null for missing ID
+
+Root cause: Test setup adds a user with ID 'test-id' but queries with 'missing-id'.
+Fix: Updated test to query with 'missing-id' — setup was correct, query was wrong.
+
+```
+$ flutter test test/unit/data/user_repository_test.dart
+1 test passed.
+```
+
+## Fix 2: Widget Test
+
+File: test/widget/cart_page_test.dart
+Failure: Empty state text widget not found
+
+Root cause: Empty state message was renamed from 'Your cart is empty' to 'Cart is empty' in the widget.
+Fix: Updated test string to match current widget copy.
+
+```
+$ flutter test test/widget/cart_page_test.dart
+1 test passed.
+```
+
+## Final Run
+
+```
+$ flutter test --coverage
+All 44 tests passed.
+Coverage: 84.2% (target: 80%)
+```
+
+## Summary
+
+| Metric | Value |
+|--------|-------|
+| Total tests | 44 |
+| Passed | 44 |
+| Failed | 0 |
+| Coverage | 84.2% |
+
+Test Status: PASS ✓
+````
+
+## Common Test Failures
+
+| Failure | Typical Fix |
+|---------|-------------|
+| `Expected: <X> Actual: <Y>` | Update assertion or fix implementation |
+| `Widget not found` | Fix finder selector or update test after widget rename |
+| `Golden file not found` | Run `flutter test --update-goldens` to generate |
+| `Golden mismatch` | Inspect diff; run `--update-goldens` if change was intentional |
+| `MissingPluginException` | Mock platform channel in test setup |
+| `LateInitializationError` | Initialize `late` fields in `setUp()` |
+| `pumpAndSettle timed out` | Replace with explicit `pump(Duration)` calls |
+
+## Related Commands
+
+- `/flutter-build` — Fix build errors before running tests
+- `/flutter-review` — Review code after tests pass
+- `/tdd` — Test-driven development workflow
+
+## Related
+
+- Agent: `agents/flutter-reviewer.md`
+- Agent: `agents/dart-build-resolver.md`
+- Skill: `skills/flutter-dart-code-review/`
+- Rules: `rules/dart/testing.md`