exhaustive-testing

Unit tests should verify logic for each public method using mocks to isolate dependencies. Write tests alongside implementation to catch issues early, ensuring comprehensive coverage of method inputs, outputs, and edge cases before integration.

Unit tests verify individual methods in isolation; integration tests check module interfaces work together; end-to-end tests validate complete workflows; regression tests reproduce and prevent known bugs. Exhaustive testing uses all four to ensure complete coverage across your codebase.

Integration tests verify that modules communicate correctly by testing interactions between components, checking data flows between layers, and validating shared interfaces. They catch issues that unit tests miss by testing real module interactions.

Use manual testing for scenarios where automation is infeasible—complex user workflows, visual validation, or exploratory testing. Document manual test cases comprehensively to ensure realistic usage scenarios are validated when automation cannot cover them.

Create regression tests that reproduce the bug and verify the fix prevents it from recurring. Write these tests during bug investigation to catch the failure, then validate the fix passes the test, preventing the same bug in future releases.

Reliable tests produce consistent results regardless of execution order or environment by avoiding external dependencies, using fixed test data, and eliminating timing issues. Deterministic tests ensure confidence in code changes and catch real bugs rather than false failures.