如何从另一个模拟继承一个模拟？

Question

假设我有这个示例代码：

interface IBase {
    int BaseProperty { get; }
}
interface IDerived : IBase {
    int DerivedProperty { get; }
}

并且我喜欢为两个接口编写模拟。

基本模拟很简单：

class BaseMock : Mock<IBase> {
    public int BaseProperty { get; set; } = 42;
    public BaseMock() {
        SetupGet(o => o.BaseProperty).Returns(BaseProperty);
    }
}

但我不确定如何正确编写派生模拟：

class DerivedMock : Mock<IDerived> {
    public int BaseProperty { get; set; } = 42;
    public int DerivedProperty { get; set; } = 73;
    public DerivedMock() {
        // setups related to IBase
        SetupGet(o => o.BaseProperty).Returns(BaseProperty);

        // setups related to IDerived
        SetupGet(o => o.DerivedProperty).Returns(DerivedProperty);
    }
}

此实现将按预期工作，但我被迫在此处复制 BaseMock 类的基本全部内容，而这不是 DRY ...

理想情况下，我想从 BaseMock 继承 DerivedMock ，但是与 IDerived 相关的设置将无法编译（o 是IBase 和我它是IDerived）...

我很欣赏任何朝着正确方向的努力:)

Answer 1

Rafał Rutkowski 把我踢向了正确的方向，我最终为其他感兴趣的人提供了这段代码：

interface IBase {
    int BaseProperty { get; }
}
interface IDerived : IBase {
    int DerivedProperty { get; }
}

class BaseMock : Mock<IBase>, IBase {
    public int BaseProperty { get; set; } = 42;

    public BaseMock() {
        SetupAll(this, this);
    }

    public static void SetupAll<TBase>([NotNull] Mock<TBase> mock, [NotNull] TBase instance)
        where TBase : class, IBase {
        mock.SetupGet(o => o.BaseProperty).Returns(instance.BaseProperty);
    }
}


class DerivedMock : Mock<IDerived>, IDerived {
    public int BaseProperty { get; set; } = 42;
    public int DerivedProperty { get; set; } = 73;

    public DerivedMock() {
        SetupAll(this, this);
    }

    public static void SetupAll<TDerived>([NotNull] Mock<TDerived> mock, [NotNull] TDerived instance) 
        where TDerived : class, IDerived {
        BaseMock.SetupAll(mock, instance);
        mock.SetupGet(o => o.DerivedProperty).Returns(instance.DerivedProperty);
    }
}

public class UnitTest1
{
    public void Test() {
        BaseMock baseMock = new BaseMock();
        IBase baseObject = baseMock.Object;

        baseMock.BaseProperty = 37;
        Assert.AreEqual(37, baseObject.BaseProperty);
        baseMock.VerifyGet(o => o.BaseProperty, Times.Never);
        
        // ----------------

        DerivedMock derivedMock = new DerivedMock();
        IDerived derivedObject = derivedMock.Object;

        derivedMock.BaseProperty = 42;
        derivedMock.DerivedProperty = 73;
        Assert.AreEqual(42, derivedObject.BaseProperty);
        Assert.AreEqual(73, derivedObject.DerivedProperty);
    }
}

我以这种方式编写它的原因是我可以动态更改属性值并验证它是否被读取/写入。

Answer 2

您不是从 Mock 类继承的。相反，您可以使用 Mock 的 Object 属性来获取模拟对象。要重用设置 IBase 模拟，您可以执行以下操作：

    private static void SetupBase<T>(Mock<T> mock)
        where T : class, IBase
    {
        // setup base methods and properties
        mock.SetupGet(x => x.BaseProperty).Returns(1);
    }

    private static void SetupDerived(Mock<IDerived> mock)
    {
        SetupBase(mock);

        // setup derived methods and properties
    }

    [Test]
    public void Test()
    {
        var derivedMock = new Mock<IDerived>();
        SetupDerived(derivedMock);
        var derived = derivedMock.Object;

        Assert.AreEqual(1, derived.BaseProperty);

        derivedMock.SetupGet(x => x.BaseProperty).Returns(2);
        Assert.AreEqual(2, derived.BaseProperty);
    }