I’ve found that his zero-knowledge approach gives me a suite of tests that have high signal when they fail.

Sandi Metz has also spoken extensively on testing, and I particularly like her advice on using mocks in tests appropriately. This talk of hers on the subject comes to mind: https://youtu.be/URSWYvyc42M

For years I felt like a terrible tester on a team of even worse testers. I still catch myself using antipattetms I tell other people not to use.

Honestly the two biggest things I know are try to write pure functions, and separate deciding from doing (these are not mutally exclusive), something Meyer also talked about. That will open up a lot of your code to simple tests with few mocks.

Book advice is going to sound like a non sequitur. I find bad habits in many of the testing books I’ve read, like the author hasn’t root caused common problems that pop up on real teams. You can’t blame human frailty for your testing problems. Testing is a monument to human fallability. Own it.

You can fix a lot of classes of problems with Refactoring by Fowler. There’s a second edition due out in a few months. I hope it maintaina the value judgements and thought processes if the original.