Mocha and Chai

• What is Mocha Framework?

Mocha is a JavaScript test framework for Node.js programs, featuring browser support, asynchronous testing, test coverage reports, and use of any assertion library.

describe('Foo', function(){
  describe('#bar()', function(){
    it('should work without error', function(done){
      var foo = new Foo(128);
      foo.bar(done);
    })
  })

})

describe():To group the tests

it(): Individual test case
context() is just an alias for describe(), and behaves the same way; it just provides a way to keep tests easier to read and organized. Similarly, specify() is an alias for it().

describe('Hooks', function() {
  before(function() {
    // runs once before all tests in the block
  })

  after(function() {
    // runs once after all tests in the block
  })

  beforeEach(function() {
    // runs before each test in the block
  })

  afterEach(function() {
    // runs after each test in the block
  })

})

• Chai

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework. 

expect(), should(), assert() -style assertions