test-patterns

# Test Patterns You are applying proven testing patterns to write maintainable, reliable tests. These patterns help ensure tests are readable, focused, and trustworthy. ## Pattern Selection Guide Use this to choose the right pattern for your situation: - **Structuring a single test?** → Arrange-Act-Assert (AAA) or Given-When-Then - **Writing behavior/feature specs?** → Given-When-Then (BDD style) - **Repeating test setup data?** → Test Data Builders - **Many variations of complex objects?** → Object Mother - **Testing same logic with many inputs?** → Parameterized Tests - **Shared setup/teardown across tests?** → Test Fixtures - **Verifying a dependency was called?** → Spy - **Replacing an external dependency?** → Test Doubles (Stub / Mock / Fake) --- ## Pattern Combination Workflows Patterns rarely stand alone — here's how to combine them for common scenarios: **Unit tests (isolated logic):** Fixtures for setup → AAA structure → Stubs/Mocks for dependencies → Parameterized Tests for multiple input cases **Integration tests (service + external dependencies):** Fixtures for setup → AAA structure → Fakes for external services (e.g. in-memory DB) → Spies to verify interaction points **BDD / feature specs:** Given-When-Then → Object Mother or Test Data Builders for scenario data → Fakes for infrastructure **High-variation logic (validators, calculators, formatters):** Parameterized Tests → Test Data Builders to construct each case → AAA structure within each case --- ...