如何在nunit中正确获取控制器的结果？

[TestFixture]
public class MyControllerTests
{
    [Test]
    public void MyAction_Returns_ViewResult()
    {
        // Arrange
        var controller = new MyController();

        // Act
        var result = controller.MyAction();

        // Assert
        Assert.IsInstanceOf<ViewResult>(result);
        var viewResult = (ViewResult)result;
        Assert.AreEqual("MyView", viewResult.ViewName);
        Assert.IsInstanceOf<MyModel>(viewResult.Model);
    }

    [Test]
    public void MyAction_Returns_JsonResult()
    {
        // Arrange
        var controller = new MyController();

        // Act
        var result = controller.MyAction();

        // Assert
        Assert.IsInstanceOf<JsonResult>(result);
        var jsonResult = (JsonResult)result;
        Assert.AreEqual("Success", jsonResult.Data);
    }

    [Test]
    public void MyAction_Returns_RedirectResult()
    {
        // Arrange
        var controller = new MyController();

        // Act
        var result = controller.MyAction();

        // Assert
        Assert.IsInstanceOf<RedirectResult>(result);
        var redirectResult = (RedirectResult)result;
        Assert.AreEqual("/Home/Index", redirectResult.Url);
    }
}