c# - 在起订量上向上转换接口不起作用

Question

我正在使用最小起订量进行测试。我将对象上载到它的接口并发现了一个问题。

以下是显示问题的测试。

• 对象

  public interface IVehicle { string Model { get; } }
  public interface ICar : IVehicle { }
  public class Golf : ICar
  {
      public Golf(string model)
      {
          this.Model = model;
      }
  
      public string Model { get; private set; }
  }
  

• 测试失败

  [TestMethod]
  public void InheritanceInterface_Test_WithMoq()
  {
      string golfmodel = "gti";
      var gti = new Moq.Mock<Golf>(golfmodel).Object;
      var safeVehicle = gti as IVehicle;
      var vehicle = (IVehicle)gti;
      var safeCar = gti as ICar;
      var car = (ICar)gti;
  
      Assert.AreEqual(golfmodel, gti.Model, string.Format(" Model:{0} | Golf Model:{1}", golfmodel, gti.Model));
      Assert.AreEqual(gti.Model, safeVehicle.Model, string.Format("Golf Model:{0} | Vehicle Model:{1}", gti.Model, safeVehicle.Model));
      Assert.AreEqual(gti.Model, vehicle.Model, string.Format("Golf Model:{0} | Vehicle Model:{1}", gti.Model, vehicle.Model));
      Assert.AreEqual(gti.Model, safeCar.Model, string.Format("Golf Model:{0} | Carro Model:{1}", gti.Model, safeCar.Model));
      Assert.AreEqual(gti.Model, car.Model, string.Format("Golf Model:{0} | Carro Model:{1}", gti.Model, car.Model));
  }
  

• 测试通过

  [TestMethod]
  public void InheritanceInterface_Test()
  {
      string golfmodel = "gti";
      var gti = new Golf(golfmodel);
      var vehicle = (IVehicle)gti;
      var car = (ICar)gti;
  
      Assert.AreEqual(golfmodel, gti.Model, string.Format(" Model:{0} | Golf Model:{1}", golfmodel, gti.Model));
      Assert.AreEqual(gti.Model, vehicle.Model, string.Format("Golf Model:{0} | Vehicle Model:{1}", gti.Model, vehicle.Model));
      Assert.AreEqual(gti.Model, car.Model, string.Format("Golf Model:{0} | Carro Model:{1}", gti.Model, car.Model));
  }
  

如何更改它，以便当我将Mock<Golf>.Object其转换为其中一个接口时，我仍然可以访问该Model属性？

Answer 1

默认情况下，当您 Mock 一个具体类型时，Moq 不会调用虚拟方法或实现接口。只有当你告诉它它可以调用基本实现时它才会这样做，否则它会假设你要设置这些方法，如果你需要调用它们。如果您将测试更改为以下内容，它将起作用：

[TestMethod]
public void InheritanceInterface_Test_WithMoq()
{
    string golfmodel = "gti";
    var golfMock = new Moq.Mock<Golf>(golfmodel);

    golfMock.CallBase = true;  // Tell the mock to call base methods

    var gti = golfMock.Object;
    var safeVehicle = gti as IVehicle;
    var vehicle = (IVehicle)gti;
    var safeCar = gti as ICar;
    var car = (ICar)gti;

    Assert.AreEqual(golfmodel, gti.Model, string.Format(" Model:{0} | Golf Model:{1}", golfmodel, gti.Model));
    Assert.AreEqual(gti.Model, safeVehicle.Model, string.Format("Golf Model:{0} | Vehicle Model:{1}", gti.Model, safeVehicle.Model));
    Assert.AreEqual(gti.Model, vehicle.Model, string.Format("Golf Model:{0} | Vehicle Model:{1}", gti.Model, vehicle.Model));
    Assert.AreEqual(gti.Model, safeCar.Model, string.Format("Golf Model:{0} | Carro Model:{1}", gti.Model, safeCar.Model));
    Assert.AreEqual(gti.Model, car.Model, string.Format("Golf Model:{0} | Carro Model:{1}", gti.Model, car.Model));
}