mocha is a javascript test framework. It works well for both node.js and browser. It makes asynchronous testing simple and easy. Mocha test run serially. mocha is open source.

Installing mocha globally:

npm install -g mocha

With the above installation, mocha runs with commands:

mocha test

But, I like to run my mocha test with command npm test. To do this, add the below lines of code in your package.json:

"scripts": {
  "test": "mocha test"
}

then

npm run

Creating/Running test cases:
 

var assert = require('assert');
describe('Summation', function() {
  it('success: It should return 3', function() {
      assert.equal(3, 2+1);
  });
  it('failure: It should fail.', function() {
      assert.equal(3, 2+0);
  });

});

To run, use command:

mocha index

or

npm test

It produces:
 

  Summation
     success: It should return 3
    1) failure: It should fail.


  1 passing (9ms)
  1 failing

  1) Summation failure: It should fail.:

      AssertionError: 3 == 2
      + expected - actual

      -3
      +2
      
      at Context.<anonymous> (index.js:7:14)