How can I setup a multi-item list with moq

Question

I'm trying to write a unit test for my method but failed. I want to return the list with the 2 item response of GetMyRequest with Mock( package Moq ), then I run Task.WhenAll with the response returned with my method. So I used the SetupSequence method but it returned a single-item list. How can I return a multi-item list in my test.

public void MyMethod()
{
    ProductService = new Mock<IProductService>();
    var myResponse = myStringList.Select(async x => await _myService.GetMyRequest(x, null, null)).ToList();

    //my response type -> List<Task<ResponseModel>>

    var myResponses = await Task.WhenAll(myResponse);
}

I want myResponses multi-item list with mocking but it single-item.

Unit tests

public async Task InitializeAsync(){
    ServiceResponse = Fixture.Build<MyModel>().CreateMany(2).ToList();
    MyService = new Mock<IProductService>();
    MyService.SetupSequence(service => service.GetMyRequest(It.IsAny<string>(), null, null))
                      .ReturnsAsync(ServiceResponse[0])
                      .ReturnsAsync(ServiceResponse[1]);
}

Answer 1

TL; DR: You can't return multiple items for your GetMyRequest

---

SetupSequence means that you want to setup your GetMyRequest in a way that multiple calls against it will result with different responses.

• For the first call you will receive the value of ServiceResponse[0]
• For the second call you will receive the value of ServiceResponse[1]

According to my understanding the return type of GetMyRequest is Task<ServiceResponse> , that's why you can't define a mock to return Task<IEnumerable<ServiceResponse>> or something similar.