how to mock (awaitable) System.Threading.Tasks.Task<EMCResponse> in c#

Question

I am novice to C# and have been trying to mock an object of type System.Threading.Tasks.Task<EMCResponse> but could not succeed. Can anyone help me how to mock?

public class PEProcessor : IPEProcessor
{
    public PEProcessor(IService service)
    {
        _proxy = service;
        _emUpdate = new EMUpdate(service);
    }


    public void CreateAddress(string modelName, string version, string name, MType mType, Address address, EMRequest request)
    {
        var response = _proxy.EMCreateAsync(request); // should return object of type (awaitable) System.Threading.Tasks.Task<EMCResponse>
        address.Id = Convert.ToInt32(response.Result.CM[0].Code);
    }

}

I am mocking as below

[Fact]
public void RequestIsVerifiable()
{

    //Arrange
    var wcfMock = new Mock<IService>();

    // wcfMock.Setup(x => x.EMCreateAsync(It.IsAny<EMCreateRequest>())).ReturnAsync(??);

    //Act
    var peProcessor = new PEProcessor(wcfMock.Object);
    peProcessor.CreateAddress(MoqData.ModelName, MoqData.version, MoqData.name,
        MoqData.MType, MoqData.AddressesList(), MoqData.EMRequest);

    //Assert
    wcfMock.Verify(service => service.EMCreateAsync(It.IsAny<EMCreateRequest>()), Times.AtLeastOnce);
}

Thanks in advance!!

Answer 1

Then you need to setup the mock to return the expected result so that the test can be exercised as expected.

var response = new EMCResponse {
    //populate
};

wcfMock
    .Setup(x => x.EMCreateAsync(It.IsAny<EMCreateRequest>()))
    .ReturnAsync(response);

That said, If it is possible to refactor that code to be async all the way and not have to make blocking calls.

public class PEProcessor : IPEProcessor {
    public PEProcessor(IService service) {
        _proxy = service;
        _emUpdate = new EMUpdate(service);
    }    

    public async Task CreateAddress(string modelName, string version, string name, MType mType, Address address, EMRequest request) {
        var response = await _proxy.EMCreateAsync(request); // should return object of type (awaitable) System.Threading.Tasks.Task<EMCResponse>
        address.Id = Convert.ToInt32(response.CM[0].Code);
    }
}

The can be exercised as follows

[Fact]
public async Task RequestIsVerifiable() {

    //Arrange
    var wcfMock = new Mock<IService>();

    var response = new EMCResponse {
        //populate
    };

    wcfMock
        .Setup(x => x.EMCreateAsync(It.IsAny<EMCreateRequest>()))
        .ReturnAsync(response);

    var peProcessor = new PEProcessor(wcfMock.Object);

    //Act        
    await peProcessor.CreateAddress(MoqData.ModelName, MoqData.version, MoqData.name,
        MoqData.MType, MoqData.AddressesList(), MoqData.EMRequest);

    //Assert
    wcfMock.Verify(service => service.EMCreateAsync(It.IsAny<EMCreateRequest>()), Times.AtLeastOnce);
}