testing-best-practices

The test pyramid guides the optimal distribution of unit, integration, and e2e tests. It recommends a broad base of fast unit tests, supported by fewer integration tests and a minimal top layer of e2e tests.

To write a unit test using the Arrange-Act-Assert pattern, structure your test into three phases: set up necessary preconditions and data, execute the specific function being tested, and verify the actual output against expected results.

Test doubles are objects used to replace real dependencies in unit tests. Use mocks to verify interactions, stubs to provide predefined return values, and fakes to simulate lightweight working implementations of complex dependencies.

The FIRST principles state that tests should be Fast, Independent, Repeatable, Self-validating, and Timely. Adhering to these principles ensures your testing suite remains maintainable, reliable, and provides immediate feedback during development.

Common testing anti-patterns include multiple assertions within a single test and using non-descriptive test names. Avoiding these by keeping tests focused on single behaviors and using clear naming conventions greatly improves long-term maintainability.