The last “thinking type” debugging method is the use of test cases. This probably sounds a bit peculiar distinguishes debugging

from testing. However, consider two types of test cases: test cases for testing, where the purpose of the test

cases is to expose a previously undetected error, and test cases for debugging, where the purpose is to provide information useful in locating a suspected error. The difference between the two is that test cases for testing tend to be “fat” because you are trying to cover many conditions in a small number of test cases. Test cases for debugging, on the other hand, are “slim”

since you want to cover only a single condition or a few conditions in each test case.

In other words, after a symptom of a suspected error is discovered, you write variants of the original test case to attempt to pinpoint the error. Actually, this method is not an entirely separate method; it often is used in conjunction with the induction method to obtain information needed to generate a hypothesis and/or to prove a hypothesis. It also is used with the deduction method to eliminate suspected causes, refine the remaining hypothesis, and/or prove a hypothesis.