The document is an introduction to mutation testing presented by Jeanne Boyarsky. It discusses how mutation testing can determine if test cases are good beyond just test coverage by introducing faults into code to see if tests catch the errors. The presentation demonstrates using PitClipse, a tool that makes mutation testing easy to run, and shows test results including mutants that were killed and survived. Tips are provided on using mutation testing including ensuring initial tests pass and watching the console output.

1. Intro to Mutation Testing
slideshare.net/boyarsky
Twitter @jeanneboyarsky
Blog: http://www.selikoff.net
Jeanne Boyarsky
NY Java SIG
12/5/16

2. @jeanneboyarsky
Pause for a Commercial

3. Why write tests?
@jeanneboyarsky
It used
to work!

4. How know if tests are good?
@jeanneboyarsky

5. If test coverage low
@jeanneboyarsky
Write more tests!
Not ready
for mutation
testing of class

6. If test coverage high
@jeanneboyarsky
All done!
Perfect
code!

7. Or is it?Why is it
saying
nobody is
registered?

8. Code Review!

9. That’s a mutant!

10. Too many mutants!
They’re
everywhere!

11. PitClipse to the rescue!

12. Easy to run

13. The console flies by

14. We caught 5 mutants

15. More detail

16. The mutants live….

17. Level up

18. Now 32 survived

19. Demo

20. Tips
• JUnit tests must pass
• Watch console to see if still running
• Reports on whole project
• Fixing one may take care of more
@jeanneboyarsky