It's Two-Headed Turtles All The Way Down: An Introduction to Mutation Testing

What if we could measure the amount of code that could be changed and our tests would still pass? That’s mutation testing, and we’ll explore how we can use it to improve the code and tests that we write.

“Code coverage” is often the first and last metric used to evaluate a test suite, but this number is only the percentage of code that is executed by the tests. What if we could measure the amount of code that could be changed and our tests would still pass? That’s mutation testing, and we’ll explore how we can use it to improve the code and tests that we write.