tdd

Test-driven development is a test-first practice where you write a failing test, implement the minimal code to pass it, and then refactor safely. This red-green-refactor cycle builds reliable software through incremental, behavior-focused iterations.

To write behavior-focused integration tests, validate public interfaces and expected outcomes rather than internal implementation details. Define the desired behavior first, write a failing test, then implement the smallest solution to make it pass.

Mocking in integration tests should be used to define boundaries around external dependencies. By mocking these boundaries, you ensure your behavior-focused tests remain reliable and validate your public interfaces without coupling to fragile implementation details.

The best way to fix a bug using test-first development is to write a failing test that reproduces the exact behavior issue. Once the test fails, implement the smallest fix to make it pass, then refactor the code to improve maintainability.

Yes, test-driven development works for both bug fixes and feature development by enforcing incremental changes. You define expected behavior upfront, write a failing test, and apply the red-green-refactor cycle to ensure reliable public interfaces.

Tests break during refactoring when they are coupled to implementation details rather than public interfaces. Behavior-focused testing prevents this by validating expected outcomes through integration tests, allowing you to refactor internal code safely.