tdd

Start Test-Driven Development by writing a test that verifies a specific behavior through the public interface, then implement the minimal code to pass it. This Skill guides you through incremental RED-GREEN-REFACTOR cycles to build features reliably using vertical slices.

Vertical slicing in TDD is building small, testable units of functionality incrementally. It improves code quality by ensuring each slice addresses a verified need through tracer bullets, keeping implementation focused on behavior rather than unnecessary details.

You should refactor code during the REFACTOR phase of the TDD cycle, which occurs only after the test passes and functionality is verified. This Skill provides guidance on improving code structure while maintaining robust, testable behavior.

Test-Driven Development should focus on verifying behavior through public interfaces, not implementation details. This approach ensures your tests remain robust and maintainable, allowing you to refactor internal code without constantly breaking the test suite.

The best way is to write a test for the login success scenario, implement the minimal code to pass, and repeat for other cases like invalid credentials. This Skill uses tracer bullets to drive implementation and ensure each scenario meets specification.

Yes, TDD integrates naturally with agile development by supporting incremental development cycles. This Skill emphasizes building software one step at a time, prioritizing testability and clear interface design to deliver features with confidence.