Error in Unit testing help me to solve this

I got error in this testing can anyone sove this why this happen

describe('Controller: LoginCtrl', function () { beforeEach(function(){

    var $httpBackend;
    module("loginModule");
});

beforeEach(inject(function($controller, $rootScope, $location, $auth, $httpBackend) {
    this.$location= $location;
    this.$httpBackend=$httpBackend;
    this.scope= $rootscope.$new();
    this.redirect = spyOn($location,'path');

    $controller('LoginCtrl',{
        $scope: this.scope,
        $location: $location,
        auth: $auth

    });

}));



describe("succesfully loggin in",function(){
    it("should redirect you to home",function(){
        //arrange
        $httpBackend.expectPOST('/login',scope.login).respond(200);
        //act
        scope.login();
        $httpBackend.flush();

        //assertion
        expect(this.redirect).toHaveBeenCalledWith('/login');
    });

});

});

Error i got is

    Error: [$injector:unpr] Unknown provider: $authProvider <- $auth
    http://errors.angularjs.org/1.2.28/$injector/unpr?p0=%24authProvider%20%3C-%20%24auth
        at C:/xampp/htdocs/app/bower_components/angular/angular.js:3801
        at getService (C:/xampp/app/bower_components/angular/angular.js:3929

) at C:/xampp/htdocs/app/bower_components/angular/angular.js:3806 at getService (C:/xampp/htdocs/app/bower_components/angular/angular.js:3929 ) at invoke (C:/xampp/htdocs/app/bower_components/angular/angular.js:3956) at workFn (C:/xampp/htdocs/app/bower_components/angular-mocks/angular-mocks .js:2177)

    undefined
    ReferenceError: Can't find variable: $httpBackend
        at C:/xampp/htdocs/test/spec/controllers/login.js:32

PhantomJS 1.9.8 (Windows 8): Executed 1 of 1 (1 FAILED) ERROR (0.02 secs / 0.021 secs) Warning: Task "karma:unit" failed. Use --force to continue.