Boris Beizer, identified five phases of a tester’s mental life:

Phase 0: There’s no difference between testing and debugging. Other than in support of debugging, testing has no purpose.

Phase 0 Thinking: Testing = Debugging

Phase 1: The purpose of testing is to show that the software works.

Phase 1 Thinking: The S/W Works

Phase 2: The purpose of testing is to show that the software doesn’t work.

Phase 2 Thinking: The S/W Doesn’t Work

Phase 3: The purpose of testing is not to prove anything, but to reduce the perceived risk of the software not working to an acceptable value.

Phase 3 Thinking: Test for Risk Reduction

Phase 4: Testing is not an act. It is a mental discipline that results in low-risk software without much testing effort.

Phase 4 Thinking: A State of Mind

Now think – Which tester’s mental phase are you?