.NET6 HttpClient Test Helper

HttpClientTestHelper.cs

using System.Net;
using System.Net.Http.Headers;
using Moq;
using Moq.Protected;
using Newtonsoft.Json;

namespace Example.Test.Helpers;
 
public class HttpClientTestHelper
{
    private readonly Mock<HttpMessageHandler> _mockHandler;

    public HttpClientTestHelper()
    {
        _mockHandler = new Mock<HttpMessageHandler>();
    }
    
    public HttpClientTestHelper WithResult<T>(T response, Uri requestUri)
    {
        var mockResponse = new HttpResponseMessage()
        {
            Content = new StringContent(JsonConvert.SerializeObject(response)),
            StatusCode = HttpStatusCode.OK
        };
 
        mockResponse.Content.Headers.ContentType =
            new MediaTypeHeaderValue("application/json");
 
        _mockHandler
            .Protected()
            .Setup<Task<HttpResponseMessage>>(
                "SendAsync",
                ItExpr.Is<HttpRequestMessage>(m => m.RequestUri.OriginalString.Equals(requestUri.OriginalString)),
                ItExpr.IsAny<CancellationToken>())
            .ReturnsAsync(mockResponse)
            .Verifiable();

        return this;
    }

    public Mock<HttpMessageHandler> Build()
    {
        return _mockHandler;
    }
    
}

TestClass.cs

[Fact]
public async Task Should_Mock_HttpTraffic()
{
	// Arrange
	var uri1 = new Uri("https://www.example.com/route1");
	var response = BuildExampleRoute1Response();
		
	var httpMockBuilder = new HttpClientTestHelper()
		.WithResult(response, uri1);

	if(conditionalThing)
	{
		var uri2 = new Uri("https://www.example.com/route2");
		var response2 = BuildExampleRoute2Response();
		httpMockBuilder.WithResult(response2, uri2);
	}

	var httpMock = httpMockBuilder.Build();
	var mockedHttpClient = new HttpClient(secureCloudHttpMock.Object);

	var someService = new SomeService(
		mockedHttpClient,
		_logger);
		
	// Act
	var result = await someService.GetInfo();
	
	// Assert
	Assert.NotNull(result);
	httpMockBuilder.VerifyAll();	
}