Assertions

Mocha allows you to use any assertion library you wish. In many of this site’s examples, we’re using Node.js’ built-in assert module — but generally, if it throws an Error, it will work! This means you can use libraries such as:

• better-assert - C-style self-documenting assert()
• chai - expect(), assert() and should-style assertions
• expect.js - expect() style assertions
• should.js - BDD style shown throughout these docs
• unexpected - “the extensible BDD assertion toolkit”