Testing AngularJS promises in Jasmine 2.0

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After your call to promise.resolve():

  • Call $timeout.flush(). This will force a digest cycle and propagate the promise resolution
  • Call done(). This tells Jasmine the async tests have completed

Here’s an example (Demo on Plunker):

describe('AngularJS promises and Jasmine 2.0', function() {
    var $q, $timeout;

    beforeEach(inject(function(_$q_, _$timeout_) {
        // Set `$q` and `$timeout` before tests run
        $q = _$q_;
        $timeout = _$timeout_;
    }));

    // Putting `done` as argument allows async testing
    it('Demonstrates asynchronous testing', function(done) {
        var deferred = $q.defer();

        $timeout(function() {
            deferred.resolve('I told you I would come!');
        }, 1000); // This won't actually wait for 1 second.
                  // `$timeout.flush()` will force it to execute.

        deferred.promise.then(function(value) {
            // Tests set within `then` function of promise
            expect(value).toBe('I told you I would come!');
        })
        // IMPORTANT: `done` must be called after promise is resolved
        .finally(done);

        $timeout.flush(); // Force digest cycle to resolve promises
    });
});

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