Xunit - Moq always returns a null value even after setup

Question

Hi I am having an issue with my moq when I try to return data, I saw this questtion with a solution but it doesn't work on my side.

Can anyone please tell me what I'm doing wrong

1. Here is my respository

    private readonly IRepository<SomeClass<MyObject>> repository;
    public MyObjectRepository(IRepositoryFactory factory)
    {
        repository = factory.RepositoryOf<SomeClass<MyObject>>();
    }
   
    public async Task<IEnumerable<MyObject>> GetAllAsync(string SomeParameter)
    {
        var result = await repository.GetAsync(x => x.OtherParameter == $"{SomeParameter}.{nameof(MyObject)}s", default);
        var reportDataItem = result.FirstOrDefault();
   
        if (reportDataItem == null)
            return null;
   
        return reportDataItem.Collection;
    }
   

2. Here is my test var data = await MockDBHelper.GetAirportsAsync(someParameter, true);

        mockIRepository.Setup(x => x.GetAsync(null, default)).ReturnsAsync(data);
   
        mockFactory.Setup(x => x.RepositoryOf<SomeClass<MyObject>>()).Returns(mockIRepository.Object);
   
        _repo = new MyObjectRepository(mockFactory.Object);
   
        var result = await _repo.GetAllAsync(AirlineCd);
   
        mockRepository.Verify(x => x.GetAsync(null,default), Times.Once());
   

Answer 1

This statement

mockIRepository.Setup(x => x.GetAsync(null, default)).ReturnsAsync(data);

will only return data when the values of null and the default value are passed as the two parameters. Since you are passing a function as the first parameter it is not null, therefore not matching the setup. Instead you could tell mock to "Match anything" for the function.

mockIRepository.Setup(x => x.GetAsync(It.IsAny<Func<PARAMETER_TYPE, RETURN_TYPE>>(), default)).ReturnsAsync(data);

You will need to replace PARAMETER_TYPE and RETURN_TYPE with the appropriate types used in your code.