AngularJS directive unit test

'use strict';
describe('Directive', function() {
    var $rootScope;
    var $compile;

    var compileDirective = function (markup, scope) {
        var el = $compile(markup)(scope);
        scope.$digest();
        return el;
    };

    beforeEach(module('directives'));

    beforeEach(inject(function (_$rootScope_, _$compile_) {
        $rootScope = _$rootScope_;
        $compile = _$compile_;
    }));
    
    it('spec', function(){
        var element = compileDirective('<directive />', $scope);
        expect(...);
    });
});