Extreme Programming Perspectives
Chapter 39. Jester A JUnit Test Tester
Ivan Moore Copyright © 2003, Ivan Moore. All rights reserved. Extreme Programmers have confidence in their code if it passes their unit tests. More experienced Extreme Programmers have confidence in their code only if they also have confidence in their tests. A technique used by Extreme Programmers to gain confidence in their tests is to make sure that their tests spot deliberate errors in the code. This sort of manual test testing is either time-consuming or very superficial. Jester is a test tester for JUnit tests; it modifies the source in a variety of ways and checks whether the tests fail for each modification. Jester indicates code changes that can be made that do not cause the tests to fail. If code can be modified without the tests failing, it indicates either that a test is missing or that the code is redundant. Jester can be used to gain confidence that the existing tests are adequate or to get clues about the tests that are missing. Jester is different from code coverage tools because it can find code that is executed by running tests but not actually tested by them. Results of using Jester are discussed. |