How good is your test suite? Would it all still pass if the tested code was changed? If so, there may be problems with your code, your tests, or both!

Mutation Testing reveals these cases. It makes lots of slightly altered versions of your code, called "mutants". If any mutants let all of the code's tests pass, you probably have gaps in your test suite, ineffective code, or both.

This talk will tell you what mutation testing is, how it works, how to use it, and its benefits, drawbacks, inner workings, and history. There will be several examples, and a list of tools for many popular languages.

You will come away equipped with a powerful new technique for making sure your tests are strict and your code is meaningful!