c# – 使用Moq验证使用不同对象状态的方法调用

最近我在一个C#项目中发现了Moq库(4.5.21)非常有趣的行为.以下是我要测试的课程.

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TestClass：

[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>)

我希望我可以验证方法是否每次调用一次具有不同状态的对象.关于我做错了什么的任何想法？

谢谢！

解决方法

这与 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(对于特定调用)已将其State属性更改为“open”(就在第二次调用之前).这可以通过将Order类更改为struct来证明,以确保mock捕获对象的副本而不是对对象本身的引用.

编辑：
为了得到完整的答案,上面的帖子使用的Expect现在已经过时了,这是一个通过测试：

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);