在测试web api时，单元测试结果为空对象2

Question

我是第一次接触MS Unit Testing和Moq objects。我正在尝试测试我的Web API 2控制器。我在下面给出了我的单元测试和控制器代码。在单步执行代码时，它甚至没有转到GetDeliveryCodeStrategy方法。

[TestMethod]
public void  CreateDelivery_ShouldReturnDeliveryCode()
{
    Mock<IDeliveryStrategy> deliveryStrategy = new Mock<IDeliveryStrategy> 
 ();
    Mock<IDeliveryCode> deliveryCode = new Mock<IDeliveryCode>();
    var controller = new DeliveryCodeController(deliveryStrategy.Object, 
    deliveryCode.Object);
    var controllerContext = new HttpControllerContext();
    var request = new HttpRequestMessage();
    request.Headers.Add("appToken", "a57ffa87-950e-40f4-b965-17788becac7d");

    controllerContext.Request = request;
    controller.ControllerContext = controllerContext;

    var result = controller.CreateDelivery(50) as 
    CreatedNegotiatedContentResult<IDeliveryCode>;
    Assert.IsNotNull(result);

}

public class DeliveryCodeController : ApiController
{
    IDeliveryStrategy _deliveryBatch;
    IDeliveryCode _deliveryCode;

    //Constructor dependency injection through Autofac
   public DeliveryCodeController(IDeliveryStrategy DeliveryBatch, 
   IDeliveryCode deliveryCode)
   {
        _deliveryBatch = DeliveryBatch;
        _deliveryCode = deliveryCode;
   }

   [HttpPost]
   [Route("api/DeliveryCode/{percentage}")]
   public IHttpActionResult CreateDelivery(int percentage)
   {
      String appToken = String.Empty;

    if (Request.Headers.TryGetValues("appToken", out IEnumerable<String> 
    headerValues))
    {
    appToken = headerValues.FirstOrDefault();
    }
    if (!String.IsNullOrEmpty(appToken)))
    {   
    IDeliveryContext deliveryContext = 
       _deliveryBatch.GetDeliveryCodeStrategy(percentage);  
    _deliveryCode.Code = deliveryContext.Create();
    return Created(Request.RequestUri.ToString(), _deliveryCode);    
    }
    else
    {
    return Content(HttpStatusCode.Forbidden, new Error { message = "The App 
    Token is not valid." });
    }
  }

}

当我执行“调试测试”并逐步执行代码时，deliveryContext对象在代码IDeliveryContext deliveryContext = _deliveryBatch.GetDeliveryCodeStrategy(percentage)；中显示为null

Answer 1

您必须设置Mock以返回某个特定值：

IDeliveryContext deliveryContext = // ???? - whatever you want it to be. 
                                   // Could be another Mock.
                                   // This is what the Mock will return.

Mock<IDeliveryStrategy> deliveryStrategy = new Mock<IDeliveryStrategy>();
deliveryStrategy.Setup(x => x.GetDeliveryCodeStrategy(It.IsAny<decimal>()))
    .Returns(deliveryContext);

这告诉Mock，当调用它的GetDeliveryCodeStrategy方法时，它应该返回指定的IDeliveryContext。根据您正在尝试做的事情，这可能是另一个Mock。(返回mock的mock是不可取的，但如果您刚开始，我会将该详细信息归档，然后再回来讨论。)

我猜percentage是个decimal。It.IsAny<decimal>()意味着模拟并不关心值是什么。这通常是可以的，因为您正在测试的是您的类对mock返回的对象执行的操作。

Answer 2

对于要使用的方法，您需要在模拟对象上调用Setup()：

var deliveryStrategy = new Mock<IDeliveryStrategy>();
deliveryStrategy.Setup(x => x.GetDeliveryCodeStrategy(It.IsAny<int>))
    .Returns(AMockOfDeliveryContext); //you need to mock it beforehand so you can 
                                      //use the object here