Test-Driven Development (TDD) FAQs

Question 1

What is the Iron Law in this TDD skill?

Accepted Answer

The Iron Law dictates that no production code can be written without a failing test first. If you write code before the test, the protocol requires deleting that code and starting over to ensure the test truly validates the behavior.

Question 2

What happens if I write too much code in the GREEN phase?

Accepted Answer

The TDD skill encourages writing only the minimal code necessary to pass the failing test. This prevents over-engineering and 'You Ain't Gonna Need It' (YAGNI) features that haven't been requested or tested.

Question 3

Can I use this skill for bug fixing?

Accepted Answer

Absolutely. The skill requires you to write a failing test that reproduces the bug before implementing a fix, which ensures the bug is understood and provides a permanent regression test.

Question 4

Why is it mandatory to watch the test fail (RED phase)?

Accepted Answer

Watching a test fail proves that the test is actually checking the intended functionality. If a test passes immediately, it may be testing the wrong thing or verifying existing behavior rather than the new requirement.

Test-Driven Development (TDD)

Key Features

Use Cases

Test-Driven Development (TDD)

Key Features

Use Cases