There are the F.I.R.S.T. rules for writing tests. Clean tests follow five other rules that form the above acronym:
- Fast: Tests should be fast.
- Independent: Tests should not depend on each other.
- Repeatable: Tests should be repeatable in any environment.
- Self-Validating: Tests should have a boolean output.
- Timely: Tests need to be written in a timely fashion.
Original text from Clean Code: Reference.