testing-patterns

The AAA pattern structures clear test cases using three phases: Arrange to set up necessary data and state, Act to execute the specific function under test, and Assert to verify the actual output matches the expected result.

Unit tests should be used to verify individual software components and functions in isolation, whereas integration tests are necessary to verify that different modules, external dependencies, or services interact correctly and function together as expected.

Mocking strategies for external dependencies involve substituting real services with controlled test doubles. This isolates the specific component being tested, ensures test determinism by simulating varied responses, and prevents slow network calls during execution.

Common testing anti-patterns include writing tests that depend on execution order, testing implementation details rather than public behavior, and creating overly complex test setups. This Skill guides you in avoiding these pitfalls to build maintainable suites.

Effective test data management involves creating isolated, deterministic data sets for each test case. This prevents cross-test contamination, ensures tests can run in parallel safely, and makes test failures easier to diagnose and reproduce.