Why Testing everything is an stupid idea...
I am sure you have come across managers and stake holders who says "I want my product to be 100% tested, I can not tolerate less than 100% coverage.". I can only say those folks have lack of appreciation for the complexity of testing. No software can ever be tested completely. It simply is not possible and will never be practical and cost effective. The good news is that we have Mathematics and Statistics to help. I use 3Cs - Coverage, Confidence and calculated risk as a measurability of testing of software that I work on. I will briefly discuss these 3 Cs here.. Defining the quality goal for your product should be the first step. Let's say, we decide our software product will be 99% bug free. Now let's say we are 99% confident that we will achieve that goal. When we set our goal and confidence level, then statistics like random sampling can help us get number of test cases required (99 for a set of 100 input ) . But we know that random sampling does not work very ...