c# - 如何调试这个或可能的原因？ Moq.Verify 上的用户代码未处理 System.NullReferenceException

Question

我的单元测试中有这样的东西

public class MyTestClass()
{
      private Mock<IAccountRepo> accountRepo;
       private AdminService adminService;

      [Setup]
      public void Setup()
      {
        accountRepo = fixture.Freeze<Mock<IAccountRepo>>();
        adminService = fixture.CreateAnonymous<AdminService>();
      }

      [Test]
      public Test()
      {
          accountRepo.Setup(x => x.Insert(It.IsAny<IUnitOfWork>(), It.IsAny<MyDomainObject>()));

            adminService.ApplyAdminFee(1, 1, today);

            accountRepo.Verify(x => x.Insert(It.IsAny<IUnitOfWork>(), It.Is<MyDomainObject>(a => a.Id == 1)));
      }
}

我收到这个错误。

System.NullReferenceException was unhandled by user code
  Message=Object reference not set to an instance of an object.
  Source=Anonymously Hosted DynamicMethods Assembly
  StackTrace:
       at lambda_method(Closure , MyDomainObject )
       at Moq.It.<>c__DisplayClass2`1.<Is>b__1(TValue value)
       at Moq.Match`1.Matches(Object value)
       at Moq.Matcher.Matches(Object value)
       at Moq.MethodCall.Matches(IInvocation call)
       at Moq.Mock.<>c__DisplayClassc.<VerifyCalls>b__b(IInvocation i)
       at System.Linq.Enumerable.WhereListIterator`1.MoveNext()
       at System.Linq.Enumerable.Count[TSource](IEnumerable`1 source)
       at Moq.Mock.VerifyCalls(Interceptor targetInterceptor, MethodCall expected, Expression expression, Times times)
       at Moq.Mock.Verify[T](Mock mock, Expression`1 expression, Times times, String failMessage)
       at Moq.Mock`1.Verify(Expression`1 expression, Times times)
       at Test() in 383
  InnerException: 

我不知道为什么。

编辑

我想我知道发生了什么。在我的方法中，我调用了 3 次插入方法(插入方法接受一个对象)。

所以我喜欢

accountRepo.Insert(MyDomainObject);
accountRepo.Insert(MyOtherDomainObject);
accountRepo.Insert(MyOtherOtherDomainObject);

所以也许其他 2 个插入内容覆盖了它？我该如何解决这个问题？

Answer 1

问题出在这里:It.Is<MyDomainObject>(a => a.Id == 1) .您可以从堆栈跟踪中看出。

我会这样改:It.Is<MyDomainObject>(a => a != null && a.Id == 1)