Testing rsvp Promises in Jest

rsvp-promise-testing.js

  it('should check promise', function () {
    // Given:
    var rsvp = require('rsvp');
    var holder = {val: 0};

    // When:
    var promise = new rsvp.Promise(function (resolve) { resolve(1); });
    promise.then(function (d) { holder.val = d; });

    // Then:
    expect(holder.val).toBe(0);
    jest.runAllTimers();
    expect(holder.val).toBe(1);
  });