chai js

1Chai is an assertion library with 3 different assert styles,
2namely "should", "expect" and "assert".
3
4foo.should.equal('bar');	 // Should style
5expect(foo).to.equal('bar'); // Expect style
6assert.equal(foo, 'bar');	 // Assert style
7
8It can be used to replace the default assertion styles of JavaScript testing frameworks.