Angularjs unit testing resolving promises

Question

I'm probably doing this wrong but I can't figure out how to fix it.

I want to test a controller that uses a resource (ngResource) and I want to use a Spy as a test double for the resource so it doesn't actually do the http call. In the code below I just want to test the search function in the controller.

Controller:

controllers = angular.module('app.controllers');
controllers.controller('landingCtrl', ['$scope', '$q', 'categoryResource', function ($scope, $q, categoryResource) {

    $scope.search = function (text) {
        console.log('searching for: ' + text);
        var deferred = $q.defer();
        categoryResource.query({ searchTerm: text }, function (result) {
            if (result.length == 0) {
                deferred.resolve(['No results found']);
            } else {
                deferred.resolve(result);
            }
        });
        return deferred.promise;
    }
}]);

Service:

var services = angular.module('app.services');    
services.factory('categoryResource', ['$resource', function ($resource) {
    var resource = $resource('/api/category');    
    return resource;
}]);

Spec for landingCtrl:

describe('Controller: landingCtrl ', function () {

    var $q,
        $rootScope,
        $scope;

    beforeEach(module('ngResource'));
    beforeEach(module('app.services'));
    beforeEach(module('app.controllers'));

    beforeEach(inject(function (_$rootScope_, _$q_) {
        $q = _$q_;
        $rootScope = _$rootScope_;
    }));

    // mock any depencencies, like scope. $resource or $http
    beforeEach(inject(function ($controller, $injector, categoryResource) {
        $scope = $rootScope.$new();

        spyOn(categoryResource, 'query').andCallFake(function (searchText) {
            console.log('query fake being called');
            var deferred = $q.defer();
            deferred.resolve(['Test', 'Testing', 'Protester']);
            return deferred.promise;
        });

        landingCtrl = $controller('landingCtrl', {
            '$scope': $scope,
            '$q': $q,
            'categoryResource': categoryResource
        });
    }));

    afterEach(inject(function ($rootScope) {
        $rootScope.$apply();
    }));

    it('should return words with "test" in them"', function () {
        $scope.search('test').then(function (results) {
            console.log(results);
            expect(results).toContain('Test');
        });
        $scope.$apply();
    });
});

The test executes without errors but it passes without ever resolving the promise so my code inside the "then" function never gets called. What am I doing wrong?

I've created a plunker with the above and a test that should fail:

http://plnkr.co/edit/adE6fTajgbDoM33rtbZS?p=preview

Answer 1

Your spec is mocking categoryResource.query() so it returns a promise, but your controller isn't expecting that. It calls query() and passes a callback, and within that callback it does its thing. In other words, your spec isn't testing what your controller does.

Here's your fixed spec:

spyOn(categoryResource, 'query').andCallFake(function (searchText, callback) {
    console.log('query fake being called');
    callback(['Test', 'Testing', 'Protester']);
});

...

it('should return words with "test" in them"', function () {
    var results;

    $scope.search('test').then(function (_results_) {
        console.log(results);
        results = _results_;
    });
    $scope.$apply();

    expect(results).toContain('Test');
});

Working Plunker

Notice that I have moved the expectation outside the then() callback, so your test breaks if the promise isn't resolved.