Write failing tests first, then code to pass them.
TDD cycle: write a failing test (red), write minimal code to pass (green), refactor. Drives design toward testable, modular code and provides a regression safety net. Requires discipline and suits well-understood logic better than exploratory UI work.
Write a test for a leap-year function before implementing it.
Writing tests first clarifies what the code must do, and it produces a suite that protects the design as it develops.
Write failing tests first, then code to pass them.
Writing tests first clarifies what the code must do, and it produces a suite that protects the design as it develops.
Write a failing test, write the minimum code to pass it, then tidy the code while the tests stay green.
It helps most where requirements are clear and correctness matters. For exploratory work, writing tests afterwards can be more practical.
Typical applications include writing tests for a new function before implementing its logic, specifying the behaviour of a control algorithm with examples and building a safety-critical module one failing test at a time.
Study "Unit testing" first (topic 49 of 104 in Software & Computing). It covers the groundwork this topic builds on.
Red-green-refactor. Small steps. Behaviour-driven variants.
Write a test for a leap-year function before implementing it.
The next topic is "Integration and system testing", which builds directly on this one.
It is classed as Intermediate in Software & Computing (topic 50 of 104). It is an intermediate topic. Work through the beginner topics in Software & Computing first.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.