Jest is an open source tool developed by Facebook that provides painless JavaScript unit testing. It is built on top of the Jasmine test framework, using familiar expect(value).toBe(other) assertions.
This presentation discusses how Jest is used to unit test JavaScript at Facebook, why unit testing should be as easy and painless as possible, and how to make it that easy.
[youtube 5ZEloUxx0FM]
Video producer: http://www.jsconf.eu/