pact-testing-patterns

The test pyramid is a strategy that prioritizes fast, isolated unit tests at the base, integration tests in the middle, and fewer end-to-end tests at the top. This approach maximizes speed and reliability by catching most bugs early with unit tests while maintaining meaningful coverage across all levels.

The AAA (Arrange, Act, Assert) pattern structures unit tests by setting up test data, executing the code under test, then verifying results. Use mocks and stubs to isolate the unit from dependencies, ensuring fast, deterministic tests that focus on core business logic.

End-to-end and integration tests validate complete workflows across system layers using real or near-real dependencies. Apply data-driven testing, parameterized test cases, and managed test data to maintain maintainable, repeatable coverage without brittleness.

Meaningful coverage targets core business logic and critical paths rather than pursuing arbitrary percentages. Focus on coverage analysis to identify untested branches in high-risk code, then prioritize tests that catch real failures over exhaustive line coverage.

Yes. Dependency injection decouples code from external dependencies, making it testable in isolation. Combined with mocks and spies, it enables fast unit tests that verify behavior without hitting databases, APIs, or file systems.

Apply sequential thinking to map test responsibilities: unit tests for business logic, integration tests for component interactions, and end-to-end tests for user workflows. Align automation with the test pyramid to balance coverage, speed, and maintainability across all contexts.