A frigid commitment sealed within a software test

Question

A frigid commitment sealed within a software test

I've encountered an unexpected issue while testing a service that returns a standard $q promise. Strangely, none of the promises I test seem to be resolved or rejected (specifically, the handlers from then are not being called even though the code inside the promise runs without any problems). I've attempted to force a digest on the root scope as suggested in some answers on SO, but to no avail.

Below is a concise example demonstrating the issue:

describe('promise', function(){
  jasmine.DEFAULT_TIMEOUT_INTERVAL = 500;
  let q;

  beforeEach(inject(function($q){
    q = $q;
  }));

  it('finishes', function(done){
    expect(q).toBeDefined();
    const promise = q.resolve();
    console.log(promise);
    promise.then(
      () => done(),
      () => done.fail()
    );
  });
});

What steps should I take to ensure the promise behaves as expected?

javascript angularjs jasmine angularjs-ngmock

Answer 1

Answer №1

This particular instance is designed to assist you in comprehending the functionality of $rootScope.$digest() (even if you have previously experimented with forcing a digest). Please disregard the type declarations provided, as they were initially scripted using TypeScript.

    var service: IService;
    var $rootScope: ng.IRootScopeService;
    var $q: ng.IQService;

    beforeEach(() => {
        angular.mock.module("app");
        angular.mock.inject((
            _$rootScope_: ng.IRootScopeService,
            _$q_: ng.IQService
        ) => {
            // Implement dependencies 
            $q = _$q_;
            $rootScope = _$rootScope_;
        });

        // Set up service
        service = new Service($q);
    });


    it("should call errorCallback", () => {
        let callback = {
            errorCallback: function (response: any) { /*empty function */ }
        };

        spyOn(callback, "errorCallback");

        service.connect(null)
            .catch(callback.errorCallback);

        // Execute a digest on rootScope (essential for $q implementation) 
        $rootScope.$digest();

        expect(callback.errorCallback).toHaveBeenCalled();
    });

Answer 2

This particular instance is designed to assist you in comprehending the functionality of $rootScope.$digest() (even if you have previously experimented with forcing a digest). Please disregard the type declarations provided, as they were initially scripted using TypeScript.

    var service: IService;
    var $rootScope: ng.IRootScopeService;
    var $q: ng.IQService;

    beforeEach(() => {
        angular.mock.module("app");
        angular.mock.inject((
            _$rootScope_: ng.IRootScopeService,
            _$q_: ng.IQService
        ) => {
            // Implement dependencies 
            $q = _$q_;
            $rootScope = _$rootScope_;
        });

        // Set up service
        service = new Service($q);
    });


    it("should call errorCallback", () => {
        let callback = {
            errorCallback: function (response: any) { /*empty function */ }
        };

        spyOn(callback, "errorCallback");

        service.connect(null)
            .catch(callback.errorCallback);

        // Execute a digest on rootScope (essential for $q implementation) 
        $rootScope.$digest();

        expect(callback.errorCallback).toHaveBeenCalled();
    });

Answer 3

Answer №2

To ensure proper execution, it is important to include $scope.$apply() (or $rootScope.$digest()) and define then() before calling it as shown in the modified example below:

describe('promise', function(){
  jasmine.DEFAULT_TIMEOUT_INTERVAL = 500;
  let q;
  let scope;

  beforeEach(inject(function($q, $rootScope){
    q = $q;
    scope = $rootScope.$new();
  }));

  it('finishes', function(done){
    expect(q).toBeDefined();
    const promise = q.resolve();
    promise.then(
      () => done(),
      () => done.fail()
    );
    scope.$apply();
  });
});

Answer 4

To ensure proper execution, it is important to include $scope.$apply() (or $rootScope.$digest()) and define then() before calling it as shown in the modified example below:

describe('promise', function(){
  jasmine.DEFAULT_TIMEOUT_INTERVAL = 500;
  let q;
  let scope;

  beforeEach(inject(function($q, $rootScope){
    q = $q;
    scope = $rootScope.$new();
  }));

  it('finishes', function(done){
    expect(q).toBeDefined();
    const promise = q.resolve();
    promise.then(
      () => done(),
      () => done.fail()
    );
    scope.$apply();
  });
});

A frigid commitment sealed within a software test

Answer №1

Answer №2

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