Week 7: Tests that notice a fault

This week asks what a green test run is evidence for. You find a surviving mutant and write the test that kills it, state a property and reduce a failing input to a shrunk counterexample, and catch a change that makes a red test pass by weakening the test.

Start with the notes and rerun their commands on the course fixture. The second session is a studio on your project's tests. Then use the self-check and the optional readings. The slide source follows the same sequence. The project alpha and task backlog are due this week; the syllabus says what they contain.