Comment by wmanley

Guidelines for tests that reduce maintenance burden rather than add to it:

* Test the externally visible useful properties of your system, rather than implementation details. Related: don’t bother with mocks unless there’s no other way

* Keep your tests DRY: if there’s some invariant you want to check have it appear once in your test code

* Don’t over-test: you can delete tests and checks that fully overlap with other tests

* If you need to over-test make it easy to regenerate the expected results from your implementation (characterisation tests) as espoused by the article. * the amount of testing effort should be proportional to how important the functionality is. Reduce the effort for low impact features