Unit Testing Angular Service that uses $timeout with Jasmine's Mock Clock

Question

I have a function inside one of my angular services that I\'d like to be called repeatedly at a regular interval. I\'d like to do this using $timeout. It looks something l

Answer 1

Do not make your test Async by using Jasmine's clock. Instead, use $timeout.flush() to synchronously maintain the flow of the test. It may be a bit tricky to setup, but once you get it then your tests will be faster and more controlled.

Here's an example of a test that does it using this approach: https://github.com/angular/angular.js/blob/master/test/ngAnimate/animateSpec.js#L618

Answer 2

@matsko's answer led me down the right path. I thought I'd post my "complete" solution to make it simpler to find the answer.

The thing to test

angular.module("app").service("MyService", function() {
    return {
        methodThatHasTimeoutAndReturnsAPromise: function($q, $timeout) {
            var deferred = $q.defer();
            $timeout(function() {
                deferred.resolve(5);
            }, 2000);
            return deferred.promise;
        }
    };
});

The test

describe("MyService", function() {
    var target,
        $timeout;
    beforeEach(inject(function(_$timeout_, MyService) {
        $timeout = _$timeout_;
        target = MyService;
    }));
    beforeEach(function(done) {
        done();
    });
    it("equals 5", function(done) {
        target.methodThatHasTimeoutAndReturnsAPromise().then(function(value) {
            expect(value).toBe(5);
            done();
        });
        $timeout.flush();
    });
});