Question

我正在尝试在我的应用中正确添加HttpClient，同时还允许出于单元测试目的而模拟掉客户端工厂。我使用this作为资源。

在我的 Startup.cs

中

services.AddHttpClient<IUploader, Uploader>()
    .ConfigurePrimaryHttpMessageHandler(() =>
    {
        if (somecheckismet)
            return new HttpClientHandler() { ServerCertificateCustomValidationCallback = delegate { return true; } };
        return new HttpClientHandler();
    });

还有我的 Uploader.cs

public class Uploader : IUploader
{
    private readonly HttpClient m_httpClient;

    public Uploader(HttpClient client)
    {
        m_httpClient = client;
    }

    public async Task<string> UploadData(string url, Dictionary<string, string> data)
    {
        HttpResponseMessage result;
        try
        {
            result = await m_httpClient.PostAsync(url, new FormUrlEncodedContent(data));
            if (result.StatusCode != HttpStatusCode.OK)
            {
                return "Some error message;
            }
            else
            {
                return null; // Success!
            }
        }
        catch (Exception ex)
        {
            return "Uh-oh!";
        }
    }
}

如您所见，我正在尝试将HttpClient依赖注入Uploader中。但是，既然已经完成了，如何进行Uploader的单元测试？以前，它可以用来依赖注入HttpClientHandler，而后者可以被嘲笑掉。但是，由于我现在尝试使用IHttpClientFactory，因此似乎必须注入HttpClient。

任何帮助将不胜感激。

Answer 1

似乎您可以继续模拟HttpClientHandler并使用它来创建HttpClient

public void TestMethod() 
{
    var handler = // Mock the HttpClientHandler;
    var client = new HttpClient(handler);
    var uploader = new Uploader(client);

    // Draw the rest of the owl
}

Answer 2

您实际上不需要先定下HttpClientFactory。 HttpClientFactory只是一个帮助程序类，它从池中返回HttpClient个实例。在单元测试方案中，您将直接设置HttpClient实例。 startup.cs永远不会输入图片，因为您没有启动整个应用程序。

您的Uploader类已经为单元测试设置了，因为您正在传递HttpClient实例。要围绕HttpClient进行单元测试，您无需先提出HttpClient实例，而要替换HttpMessageHandler使用的HttpClient。这是有关所有详细信息的link精彩文章

直接从文章中提取代码

// ARRANGE
var handlerMock = new Mock<HttpMessageHandler>(MockBehavior.Strict);
handlerMock
   .Protected()
   // Setup the PROTECTED method to mock
   .Setup<Task<HttpResponseMessage>>(
      "SendAsync",
      ItExpr.IsAny<HttpRequestMessage>(),
      ItExpr.IsAny<CancellationToken>()
   )
   // prepare the expected response of the mocked http call
   .ReturnsAsync(new HttpResponseMessage()
   {
      StatusCode = HttpStatusCode.OK,
      Content = new StringContent("[{'id':1,'value':'1'}]"),
   })
   .Verifiable();

// use real http client with mocked handler here
var httpClient = new HttpClient(handlerMock.Object)
{
   BaseAddress = new Uri("http://test.com/"),
};

var subjectUnderTest = new MyTestClass(httpClient);

// ACT
var result = await subjectUnderTest
   .GetSomethingRemoteAsync('api/test/whatever');

// ASSERT
result.Should().NotBeNull(); // this is fluent assertions here...
result.Id.Should().Be(1);

// also check the 'http' call was like we expected it
var expectedUri = new Uri("http://test.com/api/test/whatever");

handlerMock.Protected().Verify(
   "SendAsync",
   Times.Exactly(1), // we expected a single external request
   ItExpr.Is<HttpRequestMessage>(req =>
      req.Method == HttpMethod.Get  // we expected a GET request
      && req.RequestUri == expectedUri // to this uri
   ),
   ItExpr.IsAny<CancellationToken>()
);

如何使用类型化的客户端模拟IHttpClientFactory

2 个答案: