Ensure that each test does not just test mocks. If it does, remove the test and try again.
Ensure each test does not test implementation detail. If it does, rewrite the test so that it tests boundary behavior.
Ensure each test does not test data structure format or types. If it does, remove the test and try again.
Ensure each test does not test for removed behavior. For example, if some behavior has been deprecated, do not write a test that simply confirms the behavior no longer works.
Evaluate if the test treats the interior of the test boundary as a blackbox. You should not know anything about interior variables, function calls, or control flow.

test-driven-development