使用 Moq 验证使用不同状态的对象的方法调用

Question

最近我在我的一个 C# 项目中发现了 Moq 库 (4.5.21) 的非常有趣的行为。下面是我要测试的 class。

public class Order
{
    public string State { get; set; }
}

public interface IOrderService
{
    Task UpdateOrderAsync(Order order);
}

public class Program
{
    public async Task RunAsync(IOrderService orderService)
    {
        var order = new Order();

        order.State = "new";
        await orderService.UpdateOrderAsync(order);

        order.State = "open";
        await orderService.UpdateOrderAsync(order);
    }
}

下面是我的测试类：

[TestMethod]
public async Task TestMethod()
{
    var mock = new Mock<IOrderService>();
    await new Program().RunAsync(mock.Object);

    mock.Verify(x => x.UpdateOrderAsync(It.Is<Order>(o => o.State == "new")), Times.Once);
    mock.Verify(x => x.UpdateOrderAsync(It.Is<Order>(o => o.State == "open")), Times.Once);
}

我得到以下输出：

Moq.MockException:
Expected invocation on the mock once, but was 0 times: x => x.UpdateOrderAsync(It.Is<Order>(o => o.State == "new"))


Configured setups:
x => x.UpdateOrderAsync(It.Is<Order>(o => o.State == "new")), Times.Once
x => x.UpdateOrderAsync(It.Is<Order>(o => o.State == "open")), Times.Once

Performed invocations:
IOrderService.UpdateOrderAsync(Order<State:open>)
IOrderService.UpdateOrderAsync(Order<State:open>)

我希望我可以 Verify 每次使用不同 State 的 object 调用该方法 Once。想知道我做错了什么吗？

谢谢！

Answer 1

这看起来与 this post

非常相似

基本上是因为在调用第一个验证时，模拟持有的引用（针对特定调用）的状态属性已更改为 "open"（就在第二个验证之前）称呼）。这可以通过将 Order class 更改为结构来证明，以确保模拟捕获对象的副本而不是对对象本身的引用。

编辑：为了一个完整的答案，上面的 post 使用了现在已经过时的 Expect，这是一个通过的测试：

var mock = new Mock<IOrderService>(MockBehavior.Loose);

var newCalled = false;
var openCalledBeforeNew = false;

mock.Setup(x => x.UpdateOrderAsync(It.Is<Order>(o => o.State == "new"))).Callback(() => newCalled = !openCalledBeforeNew).Returns(Task.FromResult((object)null));
mock.Setup(x => x.UpdateOrderAsync(It.Is<Order>(o => o.State == "open"))).Callback(() => openCalledBeforeNew = newCalled).Returns(Task.FromResult((object)null));

await new Program().RunAsync(mock.Object);

Assert.IsTrue(newCalled);
Assert.IsTrue(openCalledBeforeNew);

Answer 2

设置模拟以使用回调。在回调中计算方法被调用的次数

mock.Setup(a => a.UpdateOrderAsync(It.Is<Order>(o => o.State == "new")))
    .Returns(Task.Factory.StartNew(() => { }))
    .Callback(() => countOrderStateNew++);

这里是完整的测试方法

[TestMethod]
public async Task TestMethod1()
{

  var mock = new Mock<IOrderService>();

  Order o1 = new Order() { State = "new" };

  int countOrderStateNew = 0;
  int countOrderStateOpen = 0;

  mock.Setup(a => a.UpdateOrderAsync(It.Is<Order>(o => o.State == "new")))
      .Returns(Task.Factory.StartNew(() => { }))
      .Callback(() => countOrderStateNew++);
  mock.Setup(a => a.UpdateOrderAsync(It.Is<Order>(o => o.State == "open")))
      .Returns(Task.Factory.StartNew(() => { }))
      .Callback(()=> countOrderStateOpen++);

  await new Program().RunAsync(mock.Object);

  Assert.AreEqual(1, countOrderStateNew);
  Assert.AreEqual(1, countOrderStateOpen);


}

使用 Moq 验证使用不同状态的对象的方法调用

Verify method calls using with different state of object using Moq

c#

testing

methods

moq

mocking