Mock method with Expression as parameter.

[balajis-13395]

Hi,
I have the to mock Method with expression or predicate as parameter

I need to mock the this.catalogueRepository.GetAsync(predicate).ConfigureAwait(false); in the below method

public async Task<Catalogue> AddProductDetails(int a)
{
    Expression<Func<Catalogue, bool>> predicate = a => a.ParentId == viewModel.VendorId &&
                                                     a.GlobalKey == EYConstants.GlobalKeys.Product &&
                                                     !a.IsDeleted &&
                                                     a.GlobalValue.ToLower() == viewModel.ProductName.ToLower().Trim();

    var data = await this.catalogueRepository.GetAsync(predicate).ConfigureAwait(false);
    return data;
}

I tried to mock the this.catalogueRepository.GetAsync method in the below approach. But it returns null all the time.

Xunit test.
----------

[Fact]
public async Task AddProductDetails_ReturnResult_WhenInputIsValid()
{
    #region Arrange
    var viewModel = GetAddProductRequest();
    var vendorDetail = GetVendorDetail();
    var response = GetAddProductResponse();
    Expression<Func<Catalogue, bool>> predicate = a => a.ParentId == viewModel.VendorId &&
                                                     a.GlobalKey == EYConstants.GlobalKeys.Product &&
                                                     !a.IsDeleted &&
                                                     a.GlobalValue.ToLower() == viewModel.ProductName.ToLower().Trim();
    #endregion

    #region Act
    //Mocking the method with expression as parameter.
    this.MockCatalogueRepository.Setup(x => x.GetAsync(predicate).ReturnsAsync(vendorDetail);

    var result = await manager.AddProductDetails(viewModel);
    #endregion

    #region Assert
    Assert.NotNull(result);
    Assert.IsType<string>(result);
    Assert.Equal(response, result);
    #endregion
}

Kindly help me to resolve the issue.

[bradwilson]

This isn't strictly speaking a question for xUnit.net, since we don't provide a mocking framework. My suggestion is that you ask this question of the mocking framework author(s) instead (by the syntax, I'm guessing you're probably using Moq, whose project is here: https://github.com/moq/moq4