Test-Driven Development (TDD)

When doing test-driven development a developer uses test to guide the development. The test(s) basically become a code version of the requirements. The following sequence when developing software units in TDD should thus be followed.

The steps are as follows

• Write the test Write the test for the functionality you want to implement
• Check that the test fails Check that the test you are writing actually fails (as it should, since you have not implemented the functionality yet).
• Write enough code to pass the code The idea here is to get a minimal implementation that makes all test cases pass. The motivation here is to get a initial working version of the feature.
• Check that all tests pass Check that the entire test suite passes. This means that your new feature or change does not break any other component.
• Refactor the code Since the initial implementation could be messy, refactor the code to fullfil your quality requirements
• Correct regression and Update failing tests Correct your code so that old tests (regression means that old tests are breaking) pass and/or update the failing tests.