Moq +单元测试 - System.Reflection.TargetParameterCountException:参数计数不匹配

Question

我想使用带有多参数函数的lambda,但是当我尝试调用该行时,Moq会在运行时抛出此异常mock.Object.Convert(value, null, null, null);.

System.Reflection.TargetParameterCountException: Parameter count mismatch

代码是:

var mock = new Mock<IValueConverter>();

mock.Setup(conv => conv.Convert(It.IsAny<Object>(), It.IsAny<Type>(),
    It.IsAny<Object>(), It.IsAny<CultureInfo>())).Returns((Int32 num) => num + 5);

var value = 5;
var expected = 10;
var actual = mock.Object.Convert(value, null, null, null);

实施它的正确方法是什么？

Answer 1

这是你的Returns条款.你有一个4参数方法,但你只使用1参数lambda.我运行了以下没有问题:

[TestMethod]
public void IValueConverter()
{
    var myStub = new Mock<IValueConverter>();
    myStub.Setup(conv => conv.Convert(It.IsAny<object>(), It.IsAny<Type>(), It.IsAny<object>(), It.IsAny<CultureInfo>())).
        Returns((object one, Type two, object three, CultureInfo four) => (int)one + 5);

    var value = 5;
    var expected = 10;

    var actual = myStub.Object.Convert(value, null, null, null);

    Assert.AreEqual<int>(expected, (int) actual);
}

没有例外,测试通过.

Answer 2

不是OP的答案,但可能是未来的googlers:

我有一个Callback与正在设置的方法的签名不匹配

Mock
    .Setup(r => r.GetNextCustomerNumber(It.IsAny<int>()))
    .Returns(AccountCounter++)
    .Callback<string, int>(badStringParam, leadingDigit =>
    {
        // Doing stuff here, note that the 'GetNextCustomerNumber' signature is a single int 
        // but the callback unreasonably expects an additional string parameter.
    });

这是一些重构的结果,重构工具当然无法实现Callback签名不正确