Mutation Testing with Mutant

Tests are a good tool to verify your code but how do you verify your tests? Mutation testing is a technique to evaluate the quality of your tests by programmatically mutating (i.e. making a series of small modifications to) your code and ensuring that the tests no longer pass. This talk will attempt to demonstrate the value of mutation testing and show you how to use Mutant to improve the quality of your tests and your code.

Transcript

1. flickr.com/photos/tomtolkien Mutation Testing with Mutant
2. A carpenter is only as good as their tools. flickr.com/photos/matthigh
3. What’s in your toolbox? flickr.com/photos/dk_spook
4. Editor flickr.com/photos/audringje
5. flickr.com/photos/laughingsquid Vim 1.0
6. Debugger flickr.com/photos/86639298@N02
7. Profiler flickr.com/photos/anndouglas
8. Testing
9. Testing flickr.com/photos/onepointfour
10. Code has bugs Tests are code ∴ Tests have bugs flickr.com/photos/birdseyeview
11. Code Coverage
12. twitter.com/bloerwald/status/448415935926255618
13. Mutation flickr.com/photos/tambako
14. Original def foo(arg = true) arg || fail end assert_nothing_raised { foo }
15. Mutant def foo(arg = true) arg end assert_nothing_raised { foo }
16. twitter.com/kytrinyx/status/453567958317428736
17. Demo