The TDD technique follows a tenet known as the red-green-refactor cycle, with the red state being the initial state, indicating the commencement of a TDD cycle. At the red state, the test has just been written and will fail when it is run.
The next state is the green state and it shows that the test has passed after the actual application code has been written. Code refactoring is essential to ensure code completeness and robustness. Refactoring will be repeatedly done until the code meets performance and requirement expectations:
At the beginning of the cycle, the production code to run the test against has not been written, ...
