mocha：在beforeEach中使用inject抛出Exception

Question

我编写了一个返回以下对象的测试控制器，

{hello: 'a', world: 'b'};

使用mocha按照方式测试

describe('Test suite', function(){
    let controller;

    beforeEach(window.module('app'));
    beforeEach(function(){
            inject(function($controller){
                controller = $controller('simpleController');
                console.info(controller);
            });
    });

    afterEach(function(){
       console.info("afterEach called");
    });

    describe('Controller', function(){
        it('it should have hello', function(){
            controller.should.have.property('hello')
        });

        it('it should have world', function(){
           controller.should.have.property('world');
        });
    });

});

但是，在beforeEach

中第二次调用inject时，第二个测试用例失败并出现异常

✖ "before each" hook for "it should have world"
      Chrome 57.0.2987 (Mac OS X 10.12.1)
    Error: the string "textAngular Error: A unique name is required for a Tool Definition" was thrown, throw an Error :)

如果不是我不打电话第二次注射，一切都运作良好

if (!controller) {
  inject(function($controller){
     controller = $controller('simpleController');
     console.info(controller);
  });
}

理想情况下，我希望在每个测试用例之前有一个新的控制器实例。