unit test for service with a promise

I have a service that i wrote for a project i am currently working on and i am trying to write a unit test for it. Below is the code for the service

angular.module('services').factory('Authorization', ['$q', 'Refs', function($q, Refs) {

  function isAuthorized() {
    var deferred = $q.defer();

    var authData = Refs.rootRef.getAuth();
    var adminRef;

    if(authData.google) {
      adminRef = Refs.rootRef.child('admins').child(authData.uid);
    } else {
      adminRef = Refs.rootRef.child('admins').child(authData.auth.uid);
    }

    adminRef.on('value', function(adminSnap) {
      deferred.resolve(adminSnap.val());
    });
    return deferred.promise;
  }

  return {
    isAuthorized: isAuthorized
  };
}]);

I have written a unit test for it but anytime i run the test i get this error message ' Error: Timeout - Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL.'

Below is the code for the unit test i wrote for the service:

'use strict';

describe('Authorization Service', function() {

  var Refs, $q, Authorization, authData, scope, deferred;

  beforeEach(angular.mock.module('Sidetime'));

  beforeEach(inject(function(_Refs_, $rootScope, _$q_, _Authorization_) {
    Refs = _Refs_;
    $q = _$q_;
    Authorization = _Authorization_;
  }));

  iit('return admin object', function(done) {
    var result;

    Authorization.isAuthorized = function() {
      deferred = $q.defer();
      authData = {google: 'uid:112222'};

      if(authData.google) {
        deferred.resolve(authData);
      }

      return deferred.promise;
    };

    Authorization.isAuthorized().then(function(result) { 
      console.log('result', result);
      expect(result).toEqual(authData);
      //done();
    });
  });
});

I am not sure I am writing the unit test properly. I will appreciate if someone could show be a better way of writing the unit test for this service. Thanks for your anticipated assistance.