There are several companies which are involved on the tech side, such as Modulate AI and Spirit AI. Source: about 3 years ago

Mocha as the test runner, Chai as the assertion library, and the Hardhat Chai Matchers to extend Chai with contracts-related functionality. - Source: dev.to / almost 2 years ago

Assertion library we used: Chai (comes with a lot of plugins worth exploring). - Source: dev.to / about 2 years ago

While this is fine and I could have perfectly moved all my tests to use said assertion style, I like the descriptive way Jest tests look like. As a quick way to maintain certain similarity I reached for ChaiJS, an assertion library that is mainly used with mocha. Chai offers expect like assertions that can arguably be more descriptive than Jest’s. Instead of writing expect(…).toBe(true), you’d write... - Source: dev.to / over 2 years ago

The library offers a BDD testing style and fully exploits javascript promises - the resulting tests are simple, clear and expressive. Chakram is built on node.js, mocha, chai and request. - Source: dev.to / about 3 years ago