name: testing description: This skill should be used when the user asks to "write tests", "add tests", "create test cases", or when implementing tests as part of a feature or bug fix task.

Writing Tests

Rules

1. Reuse test files - Add tests to existing files when appropriate
2. Use parametrized tests - Group cases with same expected behavior via @pytest.mark.parametrize
3. No obvious comments - Code should be self-explanatory
4. Follow existing style - Match patterns in the existing test suite
5. Imports at module level - Only import inside functions when absolutely necessary
6. Reuse fixtures - Use existing fixtures; create new ones only when needed
7. Avoid mocks when possible - Prefer real implementations for internal code; mock only external services
8. Use appropriate mocking tools - Use respx for HTTP APIs, library

Test Naming

Name tests using the pattern: test_<what>_<condition>_<outcome>

Examples:

• test_login_valid_credentials_succeeds
• test_process_payment_insufficient_funds_raises_error
• test_parse_json_invalid_input_returns_none

Test Structure

1. Test all paths - Happy path, edge cases, and error conditions
2. One assertion focus - Each test should verify one specific behavior
3. Arrange-Act-Assert - Set up, execute, verify (AAA pattern)

Common Pytest Features

• Fixtures: @pytest.fixture for shared setup/teardown
• Mocking: monkeypatch fixture for patching
• Temp files: tmp_path fixture for file system tests
• Assertions: Use pytest.raises(ExceptionType) for exception testing