test-driven-development

Test-driven development for a new API endpoint starts by writing a minimal failing unit test that defines the intended behavior, then writing the smallest amount of production code needed to make that test pass.

The red green refactor cycle is a disciplined testing workflow where you write a failing test, write minimal code to pass it, then safely improve the implementation without losing test coverage.

Fix bugs using unit tests by creating a failing test that reproduces the regression, then repairing the code to pass while avoiding mock-driven implementations or adding test-only production methods.

Test-driven development works for refactoring existing code by using repeatable unit tests to define current behavior, ensuring code improvements maintain coverage and preventing regressions during structural changes.

Test-driven development workflows result in fragile implementations when tests validate mock behavior instead of real code, or when test-only production methods are introduced, bypassing intended behavior verification.