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| -rw-r--r-- | claude-rules/testing.md | 140 | ||||
| -rw-r--r-- | claude-rules/verification.md | 42 |
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diff --git a/claude-rules/testing.md b/claude-rules/testing.md new file mode 100644 index 0000000..37ba412 --- /dev/null +++ b/claude-rules/testing.md @@ -0,0 +1,140 @@ +# Testing Standards + +Applies to: `**/*.py`, `**/*.ts`, `**/*.tsx`, `**/*.js`, `**/*.jsx` + +## Test-Driven Development (Default) + +TDD is the default workflow for all code, including demos and prototypes. **Write tests first, before any implementation code.** Tests are how you prove you understand the problem — if you can't write a failing test, you don't yet understand what needs to change. + +1. **Red**: Write a failing test that defines the desired behavior +2. **Green**: Write the minimal code to make the test pass +3. **Refactor**: Clean up while keeping tests green + +Do not skip TDD for demo code. Demos build muscle memory — the habit carries into production. + +### Understand Before You Test + +Before writing tests, invest time in understanding the code: + +1. **Explore the codebase** — Read the module under test, its callers, and its dependencies. Understand the data flow end to end. +2. **Identify the root cause** — If fixing a bug, trace the problem to its origin. Don't test (or fix) surface symptoms when the real issue is deeper in the call chain. +3. **Reason through edge cases** — Consider boundary conditions, error states, concurrent access, and interactions with adjacent modules. Your tests should cover what could actually go wrong, not just the obvious happy path. + +### Adding Tests to Existing Untested Code + +When working in a codebase without tests: + +1. Write a **characterization test** that captures current behavior before making changes +2. Use the characterization test as a safety net while refactoring +3. Then follow normal TDD for the new change + +## Test Categories (Required for All Code) + +Every unit under test requires coverage across three categories: + +### 1. Normal Cases (Happy Path) +- Standard inputs and expected use cases +- Common workflows and default configurations +- Typical data volumes + +### 2. Boundary Cases +- Minimum/maximum values (0, 1, -1, MAX_INT) +- Empty vs null vs undefined (language-appropriate) +- Single-element collections +- Unicode and internationalization (emoji, RTL text, combining characters) +- Very long strings, deeply nested structures +- Timezone boundaries (midnight, DST transitions) +- Date edge cases (leap years, month boundaries) + +### 3. Error Cases +- Invalid inputs and type mismatches +- Network failures and timeouts +- Missing required parameters +- Permission denied scenarios +- Resource exhaustion +- Malformed data + +## Test Organization + +``` +tests/ + unit/ # One test file per source file + integration/ # Multi-component workflows + e2e/ # Full system tests +``` + +## Naming Convention + +- Unit: `test_<module>_<function>_<scenario>_<expected>` +- Integration: `test_integration_<workflow>_<scenario>_<outcome>` + +Examples: +- `test_satellite_calculate_position_null_input_raises_error` +- `test_integration_telemetry_sync_network_timeout_retries_three_times` + +## Test Quality + +### Independence +- No shared mutable state between tests +- Each test runs successfully in isolation +- Explicit setup and teardown + +### Determinism +- Never hardcode dates or times — generate them relative to `now()` +- No reliance on test execution order +- No flaky network calls in unit tests + +### Performance +- Unit tests: <100ms each +- Integration tests: <1s each +- E2E tests: <10s each +- Mark slow tests with appropriate decorators/tags + +### Mocking Boundaries +Mock external dependencies at the system boundary: +- Network calls (HTTP, gRPC, WebSocket) +- File I/O and cloud storage +- Time and dates +- Third-party service clients + +Never mock: +- The code under test +- Internal domain logic +- Framework behavior (ORM queries, middleware, hooks) + +## Coverage Targets + +- Business logic and domain services: **90%+** +- API endpoints and views: **80%+** +- UI components: **70%+** +- Utilities and helpers: **90%+** +- Overall project minimum: **80%+** + +New code must not decrease coverage. PRs that lower coverage require justification. + +## TDD Discipline + +TDD is non-negotiable. These are the rationalizations agents use to skip it — don't fall for them: + +| Excuse | Why It's Wrong | +|--------|----------------| +| "This is too simple to need a test" | Simple code breaks too. The test takes 30 seconds. Write it. | +| "I'll add tests after the implementation" | You won't, and even if you do, they'll test what you wrote rather than what was needed. Test-after validates implementation, not behavior. | +| "Let me just get it working first" | That's not TDD. If you can't write a failing test, you don't understand the requirement yet. | +| "This is just a refactor" | Refactors without tests are guesses. Write a characterization test first, then refactor while it stays green. | +| "I'm only changing one line" | One-line changes cause production outages. Write a test that covers the line you're changing. | +| "The existing code has no tests" | Start with a characterization test. Don't make the problem worse. | +| "This is demo/prototype code" | Demos build habits. Untested demo code becomes untested production code. | +| "I need to spike first" | Spikes are fine — then throw away the spike, write the test, and implement properly. | + +If you catch yourself thinking any of these, stop and write the test. + +## Anti-Patterns (Do Not Do) + +- Hardcoded dates or timestamps (they rot) +- Testing implementation details instead of behavior +- Mocking the thing you're testing +- Shared mutable state between tests +- Non-deterministic tests (random without seed, network in unit tests) +- Testing framework behavior instead of your code +- Ignoring or skipping failing tests without a tracking issue diff --git a/claude-rules/verification.md b/claude-rules/verification.md new file mode 100644 index 0000000..8993736 --- /dev/null +++ b/claude-rules/verification.md @@ -0,0 +1,42 @@ +# Verification Before Completion + +Applies to: `**/*` + +## The Rule + +Do not claim work is done without fresh verification evidence. Run the command, read the output, confirm it matches the claim, then — and only then — declare success. + +This applies to every completion claim: +- "Tests pass" → Run the test suite. Read the output. Confirm all green. +- "Linter is clean" → Run the linter. Read the output. Confirm no warnings. +- "Build succeeds" → Run the build. Read the output. Confirm no errors. +- "Bug is fixed" → Run the reproduction steps. Confirm the bug is gone. +- "No regressions" → Run the full test suite, not just the tests you added. + +## What Fresh Means + +- Run the verification command **now**, in the current session +- Do not rely on a previous run from before your changes +- Do not assume your changes didn't break something unrelated +- Do not extrapolate from partial output — read the whole result + +## Red Flags + +If you find yourself using these words, you haven't verified: + +- "should" ("tests should pass") +- "probably" ("this probably works") +- "I believe" ("I believe the build is clean") +- "based on the changes" ("based on the changes, nothing should break") + +Replace beliefs with evidence. Run the command. + +## Before Committing + +Before any commit: +1. Run the test suite — confirm all tests pass +2. Run the linter — confirm no new warnings +3. Run the type checker — confirm no new errors +4. Review the diff — confirm only intended changes are staged + +Do not commit based on the assumption that nothing broke. Verify. |
