Moq 在使用 It.Is 而不是 It.IsAny 进行验证时抛出 NullReferenceException

Question

运行针对我最新版本的单元测试我遇到了意外失败。这很奇怪，因为测试是针对我没有更改的代码进行的。测试看起来像这样：

[Fact]
public void My_Test()
{
    // Arrange
    var expectedValuation = new Money { Amount = 0, Currency = "GBP" };

    this.mockMoneyConverter.Setup(x => x.Convert(It.IsAny<MoneyWorks.Money>(), It.IsAny<Money>(), It.IsAny<ResolutionContext>()))
        .Returns(expectedValuation);

    var input = new QueryResults.ExistingItemResult
    {
        Balances = null
    };

    // Act
    var actual = this.target.Map<ExistingItemSummary>(input);

    // Assert
    actual.Valuation.ShouldBe(expectedValuation);

    this.mockMoneyConverter.Verify(x => x.Convert(It.Is<MoneyWorks.Money>(money => money.Amount == 0), It.IsAny<Money>(), It.IsAny<ResolutionContext>()));
}

ShouldBe 顺利通过，但 Verify 抛出错误：

 Message: 
    System.NullReferenceException : Object reference not set to an instance of an object.
lambda_method(Closure , Money )
    <>c__DisplayClass2_0`1.<Is>b__0(TValue value)
    Match`1.Matches(Object value)
    Matcher.Matches(Object value)
    MethodCall.Matches(ICallContext call)
    <>c__DisplayClass56_0.<VerifyCalls>b__0(ICallContext ac)
    WhereListIterator`1.MoveNext()
    Enumerable.Count[TSource](IEnumerable`1 source)
    Mock.VerifyCalls(Interceptor targetInterceptor, MethodCall expected, Expression expression, Times times)
    Mock.Verify[T,TResult](Mock`1 mock, Expression`1 expression, Times times, String failMessage)
    Mock`1.Verify[TResult](Expression`1 expression)

我觉得奇怪的是，如果我用通用 It.IsAny 检查替换验证，它会工作并通过：

this.mockMoneyConverter.Verify(x => x.Convert(It.IsAny<MoneyWorks.Money>(), It.IsAny<Money>(), It.IsAny<ResolutionContext>()));

原始 It.Is 检查突然开始失败有什么原因吗？

Answer 1

money.Amount == 0

如果 money 为 null，它将无法对其求值，我希望出现 null 引用异常。

如果这是您的问题，将其更改为处理 null 情况应该可以解决

It.Is<MoneyWorks.Money>(money => money != null && money.Amount == 0)

Moq 在使用 It.Is 而不是 It.IsAny 进行验证时抛出 NullReferenceException

Moq throwing NullReferenceException on Verify with It.Is but not It.IsAny

c#

unit-testing

moq