This talk was given at ViennaJS October 2024 by Lukas Stracke.
Most of us are probably familiar with code coverage. While we all love adding that 100% coverage badge in our repos, we should be aware that code coverage is limited in telling us how good our really tests are. How can we do better? Enter mutation testing!
Mutation testing is considered the gold standard for evaluating our tests' bug detection abilities and yet it's rather unknown in practise. In this talk, we'll explore the general concept, some of the reasons why it's rather a niche testing technique and then take a look at the tool(s) available in the JavaScript ecosystem.
We'll go through a live demo how to integrate the most popular MT tool (Stryker) into a JS project and I'll share my experience of using mutation testing at Sentry.