ASP.NET Core对Controller进行单元测试的完整步骤

对ViewData进行测试

我们编写Action的时候还会涉及ViewData给视图传递数据，这部分同样需要测试。修改Action代码，对ViewData进行赋值：

  public IActionResult UserInfo(string userId)
    {
      if (string.IsNullOrEmpty(userId))
      {
        throw new ArgumentNullException(nameof(userId));
      }

      var user = _userService.Get(userId);

      ViewData["title"] = "user_info";

      return View(user);
    }
   

修改测试用例，加入对ViewData的测试代码：

  [TestMethod()]
    public void UserInfoTest()
    {
      var userService = new Mock<IUserService>();
      userService.Setup(s => s.Get(It.IsAny<string>())).Returns(new User()
      {
        Id = "x"
      }) ;

      var ctrl = new UserController(userService.Object);
      Assert.ThrowsException<ArgumentNullException>(() => {
        var result = ctrl.UserInfo(null);
      });
      Assert.ThrowsException<ArgumentNullException>(() => {
        var result = ctrl.UserInfo("");
      });

      var result = ctrl.UserInfo("1");
      Assert.IsNotNull(result);
      Assert.IsInstanceOfType(result, typeof(ViewResult));

      var vr = result as ViewResult;
      Assert.IsNotNull(vr.Model);
      Assert.IsInstanceOfType(vr.Model, typeof(User));
      var user = vr.Model as User;
      Assert.AreEqual("x", user.Id);
      //对viewData进行assert
      Assert.IsTrue(vr.ViewData.ContainsKey("title"));
      var title = vr.ViewData["title"];
      Assert.AreEqual("user_info", title);
    }

对ViewBag进行测试

因为ViewBag事实上是ViewData的dynamic类型的包装，所以Action代码不用改，可以直接对ViewBag进行测试：

   [TestMethod()]
    public void UserInfoTest()
    {
      var userService = new Mock<IUserService>();
      userService.Setup(s => s.Get(It.IsAny<string>())).Returns(new User()
      {
        Id = "x"
      }) ;

      var ctrl = new UserController(userService.Object);
      Assert.ThrowsException<ArgumentNullException>(() => {
        var result = ctrl.UserInfo(null);
      });
      Assert.ThrowsException<ArgumentNullException>(() => {
        var result = ctrl.UserInfo("");
      });

      var result = ctrl.UserInfo("1");
      Assert.IsNotNull(result);
      Assert.IsInstanceOfType(result, typeof(ViewResult));

      var vr = result as ViewResult;
      Assert.IsNotNull(vr.Model);
      Assert.IsInstanceOfType(vr.Model, typeof(User));
      var user = vr.Model as User;
      Assert.AreEqual("x", user.Id);

      Assert.IsTrue(vr.ViewData.ContainsKey("title"));
      var title = vr.ViewData["title"];
      Assert.AreEqual("user_info", title);
      //对viewBag进行assert
      string title1 = ctrl.ViewBag.title;
      Assert.AreEqual("user_info", title1);
    }

设置HttpContext

我们编写Action的时候很多时候需要调用基类里的HttpContext，比如获取Request对象，获取Path，获取Headers等等，所以有的时候需要自己实例化HttpContext以进行测试。