TDD Cycle & Test-Driven Development FAQs

Question 1

How does the Red-Green-Refactor cycle work here?

Accepted Answer

The cycle starts with RED (writing a failing test), moves to GREEN (writing the minimal code needed to pass), and ends with REFACTOR (cleaning the code while keeping tests passing).

Question 2

Why is watching a test fail mandatory?

Accepted Answer

Watching a test fail proves that the test is actually testing the intended new behavior. If a test passes immediately, it isn't verifying anything new and cannot be trusted to catch future regressions.

Question 3

What is the Iron Law of this TDD skill?

Accepted Answer

The Iron Law states that no production code can be written without a failing test first. If code is written before a test, the skill mandates deleting that code and starting over from the test.

Question 4

How does this skill handle bug fixes?

Accepted Answer

For bug fixes, the skill requires writing a test that specifically reproduces the bug (RED), watching it fail, and then implementing the fix (GREEN) to ensure the bug is systematically resolved.

Question 5

When should I skip TDD using this skill?

Accepted Answer

TDD should always be used for new features, bug fixes, and refactoring. Exceptions are only permitted for throwaway prototypes, generated code, or configuration files after consulting with a human partner.

TDD Cycle & Test-Driven Development

Key Features

Use Cases

TDD Cycle & Test-Driven Development

Key Features

Use Cases