Unit testing com.js中的Mocha.js和sinon spy

我有一个虚拟的脊梁。模型

和主干。我的模型的视图如下所示：

  App.Views.NoteView = Backbone.View.extend({

    template: ...,

    initialize: function () {
        this.listenTo(this.model, "change", this.render);
        this.render();
    },

     render: function () {
        this.$el.html(this.template({
            title: this.model.get("title")
        }));
        return this;
     }
  });

对于测试，我使用mocha.js+chai+sinon，我有以下测试

 describe("App.Views.NoteView", function () {
      beforeEach(function () {
         this.view = new App.Views.NoteView({
              el: this.$fixture,
              model: new App.Models.Note()
        });
      }

      afterEach(function () {
          this.view.model.destroy();
      });

      it("my try 1", function () {
           var mySpy1 = sinon.spy(this.view, "render");

           this.view.model.set({
                 title: "a new Title"
           });

           expect(this.view.render).to.have.been.calledOnce;
       });
 }

我试图测试的是监视render方法：当我更改模型属性时，将调用render方法。但是，即使渲染正常执行，测试也会给出错误消息

'expected render to be called once but was called 0 times'

---

有什么帮助吗？

实际上，当视图初始化时，它会将渲染功能与其绑定。因此，当我们试图用spy绑定该渲染函数时，它是不允许的。为此，我们必须在视图初始化之前绑定spy

试试这个：

  var mySpy1 = null;
  describe("App.Views.NoteView", function () {
  beforeEach(function () {
     mySpy1 = sinon.spy(App.Views.NoteView.prototype, "render");
     this.view = new App.Views.NoteView({
          el: this.$fixture,
          model: new App.Models.Note()
    });
  }

  afterEach(function () {
      this.view.model.destroy();
      //Restore
      App.Views.NoteView.prototype.render.restore();
  });

  it("my try 1", function () {
       this.view.model.set({
             title: "a new Title"
       });

       expect(mySpy1.called).to.be.true;
   });

---

}

很抱歉，我不确定我是否理解它总是给出错误，还是仅当您不更改模型属性时才给出错误？更改模型标题时，渲染方法会正常调用。然而，期望产生了上述错误。无论如何，我在这里发现了类似的问题：

  var mySpy1 = null;
  describe("App.Views.NoteView", function () {
  beforeEach(function () {
     mySpy1 = sinon.spy(App.Views.NoteView.prototype, "render");
     this.view = new App.Views.NoteView({
          el: this.$fixture,
          model: new App.Models.Note()
    });
  }

  afterEach(function () {
      this.view.model.destroy();
      //Restore
      App.Views.NoteView.prototype.render.restore();
  });

  it("my try 1", function () {
       this.view.model.set({
             title: "a new Title"
       });

       expect(mySpy1.called).to.be.true;
   });