Proving that mocha executes async tests in sequence (and also shows how to use with generator functions)

mocha-async-sequence.spec.js

'use strict';

let co = require('co');
let chai = require('chai');
let expect = chai.expect;

function waitFor(duration) {
  return new Promise(function(resolve) {
    setTimeout(resolve, duration);
  });
}

describe.only('[mocha async test sequence]', function() {
  let sequence = 0;

  it('should run this #1', function() {
    return co(function *() {
      yield waitFor(1000);
      expect(sequence).to.equal(0);
      ++sequence;
    });
  });

  it('should run this #2', function() {
    return co(function *() {
      yield waitFor(500);
      expect(sequence).to.equal(1);
      ++sequence;
    });
  });

  it('should run this #3', function() {
    return co(function *() {
      yield waitFor(250);
      expect(sequence).to.equal(2);
      ++sequence;
    });
  });
});