The 2 previous tests are not really different. I mean, they are, but I don't think it tests what you want.

Maybe we need something like:
```javascript
test('whenReady is resolved when setReady is called', function(done) {
  var stub = sinon.stub();
  this.sinon.spy(App, 'setReady');

  var promise = App.whenReady();
  promise.then(stub).then(function() {
    assert.ok(App.isReady());
    sinon.assert.callOrder(App.setReady, stub);
  }).then(done, done);

  Promise.resolve().then(function() {
    App.setReady();
  });
});
```

What I want is to be sure that the whenReady promise is not resolved before setReady is called.