Angular服务的Jasmine测试不能解决延迟呼叫

Question

I'm pretty new to Angular and I am working to test an Angular service that runs off an API level service which wraps a bunch of calls to a REST service. Because it is working with HTTP requests, both parts of the service are working with promises and it seems to work fine, but I am having trouble getting any tests of promised behaviour working.

The relevant part of my service code ( grossly simplified ) looks like this:

angular.module('my.info')
 .service('myInfoService', function (infoApi, $q) {
    infoLoaded: false,
    allInfo: [],
    getInfo: function () {
        var defer = $q.defer();
        if (infoLoaded) {
            defer.resolve(allInfo);
        } else {
            infoApi.getAllInfo().then(function (newInfo) {
                allInfo = newInfo;
                infoLoaded = true;
                defer.resolve(allInfo);
            });
        }
        return defer.promise;
    }
});

When I am setting up my mock I have something like this:

   describe("Info Service ",
     function() {
        var infoService, infoRequestApi, $q;
        beforeEach(module("my.info"));
        beforeEach(function() {
            module(function($provide) {
                infoRequestApi = {
                   requestCount: 0,
                   getAllInfo: function() {
                       var defer = $q.defer(); 
                       this.requestCount++;
                       defer.resolve( [ "info 1", "info 2" ] );
                       return defer.promise;
                   }
                };
                $provide.value("infoApi", infoRequestApi);
            });
            inject(function( _myInfoService_, _$q_ ) {
                 infoService = _myInfoService_,
                 $q = _$q_;
            });
        });

        it("should not fail in the middle of a test", function(done) {
            infoService.getInfo().then( function(infoResult) {
                  // expectation checks.
                  expect( true ).toBeTrue();
              }).finally(done);
        });
   });

Any synchronous tests pass fine, but when I try to run any tests like this I get a message saying: Error: Timeout - Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL.

It seems as though something about the way that Angular.Mocks handles the deferred result is causing it to fail. When I step through the test, the mock object's defer variable is being set correctly, but the then statement in the service is never called. Where am I going wrong?

Answer 1

Short Answer

You have to kick off a digest cycle. You can do that with $rootScope.$apply() .

it("should not fail in the middle of a test", inject(function($rootScope) {
  var actualResult = null;
  infoService.getInfo()
    .then(function(infoResult) { actualResult = infoResult; });
  $rootScope.$apply();
  expect(actualResult).toEqual(["info 1", "info 2"]);
}));

Note

I wouldn't try to create a fake infoRequestApi service the way you are doing it. You should be injecting that service as well, and spying on its functions. For instance, something like this:

it("should not fail in the middle of a test", inject(function($rootScope, infoApi, $q) {
  var deferred = $q.defer();
  spyOn(infoApi, 'getAllInfo').and.returnValue(deferred.promise);
  var actualResult = null;
  var expectedResult = ["info 1", "info 2"];

  infoService.getInfo()
    .then(function(infoResult) { actualResult = infoResult; });

  deferred.resolve(expectedResult);
  $rootScope.$apply();
  expect(actualResult).toBe(expectedResult);
}));

Refactored

Also, your code can be simplified a bit ( untested, but close to what I would expect to see ).

angular.module('my.info')
  .service('myInfoService', function (infoApi, $q) {
     return {
       infoLoaded: false,
       allInfo: [],
       getInfo: function () {
         var self = this;
         return this.infoLoaded ? $q.resolve(this.allInfo) :
           infoApi.getAllInfo().then(function (newInfo) {
             self.allInfo = newInfo;
             self.infoLoaded = true;
           });
     }
  };
});

describe("Info Service ", function() {
  var infoService, infoApi, $q, $rootScope;

  beforeEach(module("my.info"));
  beforeEach(inject(function( _myInfoService_, _$q_ _$rootScope_, _infoApi_) {
    infoService = _myInfoService_,
    $q = _$q_;
    $rootScope = _$rootScope_;
    infoApi = _infoApi_;
  });

  it("should do something", function() { // update message
    var deferred = $q.defer();
    spyOn(infoApi, 'getAllInfo').and.returnValue(deferred.promise);
    var actualResult = null;
    var expectedResult = ["info 1", "info 2"];

    infoService.getInfo()
      .then(function(infoResult) { actualResult = infoResult; });

    deferred.resolve(expectedResult);
    $rootScope.$apply();
    expect(actualResult).toBe(expectedResult);
  });
});