Track 13 · Lesson 8 of 12

Test-driven development

Write the test first: red, green, refactor. Let small failing tests drive the design of new code and new features.

You will be able to

• Describe the red, green, refactor cycle and what each step is for
• Write a failing test for the next small behaviour before writing the code
• Write the simplest code that makes the test pass, then improve it with the tests green
• Add a feature to existing code by starting with a new failing test