Refactoring means improving the structure of code without changing its behavior.
- Consistent Behavior: To ensure that the behavior has not changed due to a refactoring, all tests must pass afterwards.
- Immediate Refactoring: Do not allow big messes to emerge, refactor as soon as possible by cleaning up small messes immediately.
Red-Green-Refactor (RGB)
This is a simple model that describes the iterative TDD and refactoring workflow:
- Write a test that initially fails. (red terminal output)
- Implement production code to pass the test. (green terminal output)
- Refactor and make sure the tests still pass.
- Repeat until done.
A more complex workflow that includes TDD and versioning with git can be found here.
Major Refactorings
For example, a major refactoring could be a large design change to the architecture. Execute large refactorings by integrating many small, incremental refactorings into your regular implementation tasks. Apply these changes within the RGB cycle whenever you encounter code that needs to be changed in line with the larger refactoring goals. This means that partial design refactorings will be in the main branch, or even in production, but this is fine as long as all the tests pass.