I think he was referring to check that the tests are actually run. This is especially useful for language that don’t complain if something looks like a test but

I think he was referring to check that the tests are actually run. This is especially useful for language that don’t complain if something looks like a test but isn’t being executed for some reason. I have written tests where I made some mistake (named the file, class, function incorrectly or forgot a parameter) and the test was never run. I would have discovered it with test coverage but I learned it the hard way (when a bug/edge case occurred for which I have written this test specifically).