I'm Christoph and I work on Jest at Facebook. We open sourced it initially 2 years ago but then abandoned it for a while. I have since worked on the project for about a year and we ramped up tons of internal and external contributors and the project is now doing really well and we have changed pretty much everything completely – except for the name of the project itself :) Jest's aim is to make JavaScript testing painless and fun.
Let me know if you have any questions, I'm happy to answer anything :)
I can highly recommend using Jest as a javascript testing framework!
Here, at Swat.io and Walls.io , we're using Jest since March (when it was 0.9.0) and it's so great so see how the framework is evolving!
I want to especially thank @cpojer for his awesome (community) work! Keep up with the good work!
Definitely recommend Jest, particularly for React apps.
I can not emphasize enough how great snapshot testing is for React. When you write a test, it generates the expected component output the first time, then checks against that snapshot in subsequent tests. This is something you do anyway, but with other frameworks you have to write the expected output yourself and keep it up to date manually.
Also, the watch features added in 15 are really groundbreaking in js test world. It's one of those simple features you'll see other suites add until we forget that it didn't exist.
Great stuff by Facebook and thanks to @cpojer in particular for his activity on reactiflux!
Jest 16
Swat.io
Polywork
ArtSquare