This is an example project implementing the well-known Tic Tac Toe game in Python in a a test-driven way. It is used as an example for teaching about test-driven development and the red-green-refactor process in my university courses.
The example is adapted from Garcia and Farcic's book Test-Driven Java Development.
The last refactoring step is missing, many things could be improved there. The purpose of the example is, however, not to show how to refactor, or how to have the cleanest implementation possible, but to illustrate the process. Thus I leave it at the current stage and do not apply any further refactorings.