Testing for me is never primarily about getting it right the first time. Although writing tests in parallel with coverage can definitely help to validate your

Testing for me is never primarily about getting it right the first time. Although writing tests in parallel with coverage can definitely help to validate your assumptions, particularly with negative testing that you might not test manually. The greater value of the tests is later on, when you need to make a change, and want to know whether you broke some existing functionality. Or, once you have a framework of tests around something, being able to quickly write a test that fails due to a discovered bug, and knowing that you fixed it by passing the test.