When I mock IHttpClientFactory and create a HttpClient, HttpClient is null

April 10, 2024

I would like to unit test a factory in which I inject IHttpClientFactory and this factory create a class that uses a HttpClient.

This is the code:

public class ClientFactory : IClientFactory
{
    private readonly IHttpClientFactory _httpClientFactory;



    public ClientFactory(IHttpClientFactory paramHttpClientFactory)
    {
        _httpClientFactory = paramHttpClientFactory;
    }



    public CLient CreateClient(ClientCofiguron paramConfiguration)
    {
        HttpClient httpClient = _httpClientFactory.Create();

        //Configure httpClient
    }
}

And this is how I try to test using xUint:

[Fact]
public async Task Create_Client()
{
    var httpClientFactory = new Mock<IHttpClientFactory>();

    IClientFactory ClientFactory = new FactoriaSolicitanteFichero(httpClientFactory.Object);
    Client = clientFactory.CreateCLient(...);
}

The problem is that in the mthod ClientFactory.CreateClient, the httpClient that is created i null, so I can use the HttpClient to create the client.

I guess that I using Moq in an incorrect way. How should I mock the HttpClientFactory?

Thank.

>Solution :

You have mocked IHttpClientFactory but not told it what to return when CreateClient is called, so it is going to return null.

You need to do this:

var httpClientFactory = new Mock<IHttpClientFactory>();
httpClientFactory
    .Setup(f => f.CreateClient(It.IsAny<string>()))
    .Returns(...<your code to create a client>...);