Updating readme with information about async tests

[Emerson]

Took me 2-days to figure this out, so I'd like to ensure others have an easier time :-)

[stefanpenner]

also, it asserts fulfillment of that promise and automatically does start/stop's for you

[Emerson]

Also, just found out that if you return a promise that rejects, it's triggers a failed test (so you need to wrap it in another promise)... which I guess is exactly what you just said!

[stefanpenner]

@Emerson sorta, that is a feature. You never want to return a "failed" promise, as that is a failure.

[Emerson]

What about a case like this? My authentication object sets error messages:

test('it sets the errors on failure', function() {
  mockHttp('/sessions', 'sessions/create_failure', 422);
  var authentication = Authentication.create();
  expect(3);
  return authentication.authenticate('test@test.com', 'wrong', true).catch(function(err) {
    equal(authentication.get('errorMessage'), 'Invalid username or password', 'errorMessage is set');
    equal(authentication.get('errors.email.firstObject'), "Invalid", 'errors object is set');
    equal(authentication.get('errors.password.firstObject'), "Invalid", 'errors object is set');
  });
});

[stefanpenner]

@Emerson catch that doesn't re-throw becomes a success. If you have an error here, you really do have a genuine test failure.

[fivetanley]

👍 Thanks! I'll add in stef's comments in a bit