Hey! I'm Christoph and I work on Jest. We wrote a blog post about how we are making Jest fast: facebook.github.io/jest/blog/2016/03/11/javascript-unit-testing-p

Hey! I'm Christoph and I work on Jest. We wrote a blog post about how we are making Jest fast: facebook.github.io/jest/blog/2016/03/11/javascript-unit-testing-performance.html If your test is fully CPU bound and limited to one core, it probably won't be faster with Jest. If you split it up across multiple files, it will parallelize tests.