While teaching a student from my SDET Lab programme, we had a good debate over what a good test is. I find Cem Kaner’s book on software testing very useful for beginners and I had given my student a copy of it as a reading exercise. A point mentioned in one of the initial chapters in Kaner’s book triggered the discussion.
From Cem Kaner’s book, a good test case is the one which finds a bug otherwise it is useless.
This is in contradiction with Kaner’s excellent definition of software testing: “Testing is an Empirical technical investigation done to provide stakeholders, information about quality of a product or a service”.
If the purpose of a testing is to provide information about the quality of something under test, IMO it holds true for a test as well.
The purpose of a test is to provide information.
So, labeling a test case as wasteful based on the outcome is wrong in my opinion. A test case that proves that there is no problem is as important as a test that proves otherwise.