How do I inject $rootScope into an AngularJS unit test?

Question

Suppose I have a service that depends on a value in $rootScope, as with the following (trivial) service:

angular.module('myServices', [])
.factory('rootValGetterService', function($rootScope) {
    return {
        getVal: function () {
            return $rootScope.specialValue;
        }
    };
});

If I want to unit test this by putting a value in $rootScope, what is the best way to go about it?

Answer 1

...
var $rootScope;
beforeEach(inject(function(_$rootScope_) {
  $rootScope = _$rootScope_;
}));
...

Answer 2

By using provide(), you can inject a new $rootScope:

describe('in rootValGetter', inject(function ($rootScope) {
    var scope;
    var testRootValGetter;

    beforeEach(function () {

        scope = $rootScope.$new();

        module(function ($provide) {
            $provide.value('$rootScope', scope);
        });

        inject(function ($injector) {
            testRootValGetterService = $injector.get('rootValGetterService');
        });
    });

    it('getVal returns the value from $rootScope', function() {
        var value = 12345;

        scope.specialValue = value;

        expect(testRootValGetterService.getVal()).toBe(value);
    }
}