Jasmine test state of object on Ajax method spy call

Question

I'm unit testing an Angular controller that uses a Rails Resource factory to handle GETing and POSTing model data from and to a Rails app. POSTing is done via a method on the model, e.g. (with a model $scope.resource):

$scope.resource.update().then(successHandler, failureHandler);

I have a spy on this method to stub out the Ajax calls so I can unit test the controller:

resUpdateSpy = spyOn($scope.resource, 'update').and.callFake(function() { 
  return {then: function(success, failure){ success(resUpdateResponse); }};
});

In one of my controller methods, I expect the resource to be POSTed with certain data (Stripe data in particular). The data will be overridden after the POST in the same method, so I cannot test the state of the model afterwards. Ideally, I would like to something like:

expect($scope.resource.update).toHaveBeenCalled().whileValueOf($scope.resource.stripeKey).isEqualTo('tok123');

Obviously, this method doesn't exist in vanilla Jasmine. Is there a way in Jasmine (either vanilla or through a third-party project) to test the state of a value when a given spy is called? or is there another way to test this situation – specifically, the state of a model before its data POSTs – that I'm missing?

I'm running Jasmine 2.2.0 with Teaspoon 1.0.2 on an Angular 1.3.14 app.

Just to clarify: do you want to test the state of the model even before you've POSTE-ed it (before you called `$scope.resource.update()`) **or** when the response from POST has come and you want to test it before it gets changed in the `then()` handler? — Michael Radionov, Jul 29 '15 at 10:24
@MichaelRadionov I want to test the state of the model before the POST. Since this is a unit test I'm stubbing the response so there's no point in testing that. — eirikir, Jul 29 '15 at 16:19

atinder · Answer 1 · 2015-08-03T03:28:55.880

you can add your own jasime matchers, the one you need would be

jasmine.Matchers.prototype.toBeResolvedWith = function() {
  var done, expectedArgs;
  expectedArgs = jasmine.util.argsToArray(arguments);
  if (!this.actual.done) {
    throw new Error('Expected a promise, but got ' + jasmine.pp(this.actual) + '.');
  }
  done = jasmine.createSpy('done');
  this.actual.done(done);
  this.message = function() {
    if (done.callCount === 0) {
      return ["Expected spy " + done.identity + " to have been resolved with " + jasmine.pp(expectedArgs) + " but it was never resolved.", "Expected spy " + done.identity + " not to have been resolved with " + jasmine.pp(expectedArgs) + " but it was."];
    } else {
      return ["Expected spy " + done.identity + " to have been resolved with " + jasmine.pp(expectedArgs) + " but was resolved with " + jasmine.pp(done.argsForCall), "Expected spy " + done.identity + " not to have been resolved with " + jasmine.pp(expectedArgs) + " but was resolved with " + jasmine.pp(done.argsForCall)];
    }
  };
  return this.env.contains_(done.argsForCall, expectedArgs);
};

more available here https://gist.github.com/gr2m/2191748

updated after comment:

basically jasmine supports custom matchers. some in built matchers are toBe, toEqual, etc. You can add your own custom matcher to check the promise.

var customMatchers = {

toHaveBeenResolved: function(util, customEqualityTesters) {
  return {
    compare: function(actual, expected) {
      var result = {};
      // do you comparison logic here
      result.pass = true/false;
      result.message = 'some message about test result';
      return result;
    }
}

this.actual is a promise and you can resolve it like this

result = {};
promise.then(function(value){
  result.value = value;
  result.status = 'Resolved';
}, function(value){
  result.value = value;
  result.status = 'Rejected';
});

once you have declared you custom matcher use it in you test case in beforeEach callback.

beforeEach(function() {
  jasmine.addMatchers(customMatchers);
});

Thanks, this looks great, but could you add further explanation? I'm not sure what, exactly, this is testing. Specifically, does `done.argsForCall` represent the model before POST (the latter is what I'm trying to test)? Also, I believe this uses syntax for Jasmine 1, but I'm on Jasmine 2.2.0 (sorry for not including this in original question, I've since updated), and this throws an error that `jasmine.Matchers` is undefined. — eirikir, Jul 29 '15 at 17:06
@atiender That makes sense on the general level, but I'm also trying to understand in particular how your `toBeResolvedWith` matcher works, so that I can adapt it to my project. Is it invoked like, `expect(myPromise).toBeResolvedWith(someResult)`? Would `this.actual` be the promise, or a representation of the promise, or something else? What is `this.actual.done`? What is `done.identity`? What is being returned? Sorry, I know these are a lot of questions; I'm not usually a JS developer so I'm not as familiar with Jasmine semantics. — eirikir, Jul 31 '15 at 15:15
updated my answer and for detailed implementation you can take a look at https://github.com/bvaughn/jasmine-promise-matchers http://jsfiddle.net/eitanp461/vjJmY/ — atinder, Aug 03 '15 at 04:07
I want to test the data *before* POST, but as far as I can tell, this custom matcher only tests the response. Is that correct? — eirikir, Aug 04 '15 at 03:56
yes it test the response. if you want to check before POST data, create a spy on the method which POST data and `expect(spy).toHaveBeenCalledWith('your data');` — atinder, Aug 04 '15 at 04:50
The `$scope.resource.update()` call will POST data from `$scope.resource` using the Rails Resource factory. This is stated in my question. How do I test this? — eirikir, Aug 04 '15 at 05:00

score 2 · Accepted Answer · answered Aug 04 '15 at 22:04

As you already have your spy forward the call to a fake function, have that fake function store the value of interest for you:

var scopeResourceStripeKeyDuringSpyCall = '(spy not called, yet)';
resUpdateSpy = spyOn($scope.resource, 'update').and.callFake(function() {
  scopeResourceStripeKeyDuringSpyCall = $scope.resource.stripeKey;
  return {then: function(success, failure){ success(resUpdateResponse); }};
});

Then just check for the stored-away value in your assertion:

expect(scopeResourceStripeKeyDuringSpyCall).toEqual('tok123');

(Depending on whether spy setup and assertion are in the same scope, the variable for storing the value might have to be less local.)

Jasmine test state of object on Ajax method spy call

2 Answers2