testing-patterns

Testing Patterns Skill

Test Structure (AAA Pattern)

def test_function_does_expected_thing():
    """Test description explaining what and why."""
    # Arrange - Set up test data and preconditions
    input_data = {"key": "value"}
    expected = "result"

    # Act - Execute the code under test
    result = function_under_test(input_data)

    # Assert - Verify the outcome
    assert result == expected

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Test Organization

tests/
├── conftest.py           # Shared fixtures
├── unit/                 # Unit tests (isolated)
│   ├── test_search_core.py
│   └── test_utils.py
├── integration/          # Integration tests
│   └── test_api.py
└── e2e/                  # End-to-end tests
    └── test_workflow.py

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Quality Targets

Metric	Target
Coverage	>70% overall
New code	100%
Core modules	>80%
No flaky tests	0

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Validation contract regressions

Mirrored validators can agree on a generated snapshot while disagreeing on real inputs. Execute the same accepted/rejected fixtures against the real backend validator and the client evaluator. Include N/N+1 boundaries, collection/item limits, omitted/null/empty/default values, nested paths, conditional branches, hydrated updates versus fresh DTOs, Unicode units and previously valid inputs.

Test the actual HTTP path for malformed input and unchanged persisted state after a pre-write refusal. Test zero transport calls for a local refusal, normal transport for a valid payload, and field correction/resubmission. Run deterministic-generation and reviewed-exclusion checks separately from behavioral parity. A schema/rule count is inventory, not assertion coverage.

For operation semantics and runtime mismatches, read reference/input-validation.md from the installed security-patterns skill. Resolve the skill through the current client's catalog; directory names may carry an adapter-specific prefix.

Language-Specific References

Language	Reference	Key Topics
Python	reference/python-pytest.md	Fixtures, mocking, parametrize, markers, conftest, running tests
TypeScript	reference/typescript-vitest.md	Vitest/Jest, React Testing Library, mocking, running tests
PHP	reference/php-phpunit.md	PHPUnit test cases, mocking, running tests
Go	reference/go-testing.md	Table-driven tests, testify mocking, running tests
Flutter/Dart	reference/flutter-testing.md	Widget tests, unit tests, running tests