Testing · Junior · Question 40 of 78

How do you make a test that uses `Math.random()` deterministic?

✓Correct answer: Mock Math.random (e.g. vi.spyOn(Math, "random").mockReturnValue(0.5)) or inject the random source
2Run the test several times and take the majority result
3Mark it with it.skip

Explanation

Random values, current time and network are the usual sources of non-determinism. Fix them in tests.

Further reading

Test yourself

Take the Testing · Junior quiz: questions and options are shuffled, and you get a review of your mistakes at the end.