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在Mock中检查更新的实例

moq mocking unit-testing c#

Russell Giddings · 技术社区 · 14 年前

我有一个方法,它调用服务来检索对象的实例,更新实例,然后将实例保存回服务(代码如下)。

我想知道的是,在最小起订量中是否有一个很好的方法来检查以下各项:-

保存回服务的实例是原始实例的修改版本
实例已按需要更新

It.Is<MyThing>(x => x.Name == newName)

有没有一个干净的方法来实现这一点?

类别代码:

public class MyClass
{
    private readonly IThingService thingService;

    public MyClass(IThingService thingService)
    {
        this.thingService = thingService;
    }

    public void SaveMyThing(MyThing myThing)
    {
        var existingThing = thingService.Get(myThing.Id);
        existingThing.Name = myThing.Name;
        thingService.Save(existingThing);
    }
}

public class MyThing
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public interface IThingService
{
    MyThing Get(int id);
    void Save(MyThing myThing);
}

[Test]
public void Save_NewName_UpdatedThingIsSavedToService()
{
    // Arrange
    var myThing = new MyThing { 
                                Id = 42,
                                Name = "Thing1"
                            };
    var thingFromService = new MyThing
                    {
                        Id = 42,
                        Name = "Thing2"
                    };

    var thingService = new Mock<IThingService>();
    thingService
        .Setup(ts => ts.Get(myThing.Id))
        .Returns(thingFromService);
    thingService
        .Setup(ts => ts.Save(**UPDATED-THING-FROM-SERVICE**))
        .Verifiable();

    var myClass = new MyClass(thingService.Object);

    // Act
    myClass.SaveMyThing(myThing);

    // Assert
    thingService.Verify();
}

3 回复 | 直到 14 年前

Jeff Sternal 14 年前

如果我理解正确,您需要验证传递给 ts.Save

如果这是真的,除了验证 Name 价值满足您的期望:

thingService
     .Setup(ts => ts.Save(It.Is<MyThing>(thing => thing == thingFromService
                                               && thing.Name = myThing.Name))
     .Verifiable();

Mark Seemann 14 年前

[Test]
public void Save_NewName_UpdatedThingIsSavedToService()
{
    // Arrange
    var myThing = new MyThing { 
                                Id = 42,
                                Name = "Thing1"
                            };
    var thingFromService = new MyThing
                    {
                        Id = 42,
                        Name = "Thing2"
                    };

    var thingService = new Mock<IThingService>();
    thingService
        .Setup(ts => ts.Get(myThing.Id))
        .Returns(thingFromService)
        .Verifiable();
    thingService
        .Setup(ts => ts.Save(It.Is<MyThing>(x => x.Name == myThing.Name)))
        .Verifiable();

    var myClass = new MyClass(thingService.Object);

    // Act
    myClass.SaveMyThing(myThing);

    // Assert
    thingService.Verify();
}

主要的区别是我还添加了一个 Verifiable() It.Is Verify

Assertion Roulette ,最好将其分为两个测试。

Greg Roberts 14 年前

相同的对象引用或对象类型 ? It.Is只是确保参数是神话 ,并不是说它是对上一个对象的实际引用。

如果要截获传递给模拟服务的值,可以使用如下回调,然后对结果对象执行任何断言:

MyThing result = null;

thingService
    .Setup(ts => ts.Save(It.Is<MyThing>(x => x.Name == myThing.Name)))
    .Callback((MyThing saved) => result = saved)
    .Verifiable();