C# 使用Moq模拟HttpClient

我想对使用

HttpClient

的类进行单元测试。我们在类构造函数中注入了

HttpClient

对象

public class ClassA : IClassA
{
    private readonly HttpClient _httpClient;

    public ClassA(HttpClient httpClient)
    {
        _httpClient = httpClient;
    }

    public async Task<HttpResponseMessage> SendRequest(SomeObject someObject)
    {
        //Do some stuff

        var request = new HttpRequestMessage(HttpMethod.Post, "http://some-domain.in");

        //Build the request

        var response = await _httpClient.SendAsync(request);

        return response;
    }
}

---

我们如何解决这个问题？

特定的重载方法不是虚拟的，因此无法被Moq覆盖

public Task<HttpResponseMessage> SendAsync(HttpRequestMessage request);

然而，模仿HttpClient并不像内部消息处理程序那样简单

我建议使用带有自定义消息处理程序存根的具体客户机，这将在伪造请求时提供更大的灵活性

下面是一个委托处理程序存根的示例

public class DelegatingHandlerStub : DelegatingHandler {
    private readonly Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> _handlerFunc;
    public DelegatingHandlerStub() {
        _handlerFunc = (request, cancellationToken) => Task.FromResult(request.CreateResponse(HttpStatusCode.OK));
    }

    public DelegatingHandlerStub(Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> handlerFunc) {
        _handlerFunc = handlerFunc;
    }

    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) {
        return _handlerFunc(request, cancellationToken);
    }
}

---

Propper使用HttpClient进行模拟是一项艰苦的工作，因为它是在大多数人在dotnet中进行单元测试之前编写的。有时，我会设置一个存根HTTP服务器，根据与请求url匹配的模式返回固定响应，这意味着您测试的是真正的HTTP请求，而不是模拟，而是本地主机服务器。使用使这变得非常简单，并且运行速度足够快，可以满足我的大部分单元测试需求

因此，与其使用

http://some-domain.in

在某些端口上使用本地主机服务器设置，然后：

var server = FluentMockServer.Start(/*server and port can be setup here*/);
server.Given(
      Request.Create()
      .WithPath("/").UsingPost()
   )
   .RespondWith(
       Response.Create()
       .WithStatusCode(200)
       .WithHeader("Content-Type", "application/json")
       .WithBody("{'attr':'value'}")
   );

---

您可以找到更多详细信息，Moq可以模拟受保护的方法，例如HttpMessageHandler上的SendAsync，您可以在其构造函数中提供给HttpClient

public class ClassA : IClassA
{
    private readonly HttpClient _httpClient;

    public ClassA(HttpClient httpClient)
    {
        _httpClient = httpClient;
    }

    public async Task<HttpResponseMessage> SendRequest(SomeObject someObject)
    {
        //Do some stuff

        var request = new HttpRequestMessage(HttpMethod.Post, "http://some-domain.in");

        //Build the request

        var response = await _httpClient.SendAsync(request);

        return response;
    }
}

var mockHttpMessageHandler=new Mock（）；
mockHttpMessageHandler.Protected（）
.Setup（“sendsync”、ItExpr.IsAny（）、ItExpr.IsAny（））
.ReturnsAsync（新的HttpResponseMessage
{
StatusCode=HttpStatusCode.OK
});
var client=新的HttpClient（mockHttpMessageHandler.Object）；

---

抄袭自

我最近不得不模仿HttpClient，我使用了。这正是我所需要的，而且使用简单，所以我想我应该把它扔掉

以下是一般用法的示例：

// All requests made with HttpClient go through its handler's SendAsync() which we mock
var handler = new Mock<HttpMessageHandler>();
var client = handler.CreateClient();

// A simple example that returns 404 for any request
handler.SetupAnyRequest()
    .ReturnsResponse(HttpStatusCode.NotFound);

// Match GET requests to an endpoint that returns json (defaults to 200 OK)
handler.SetupRequest(HttpMethod.Get, "https://example.com/api/stuff")
    .ReturnsResponse(JsonConvert.SerializeObject(model), "application/json");

// Setting additional headers on the response using the optional configure action
handler.SetupRequest("https://example.com/api/stuff")
    .ReturnsResponse(bytes, configure: response =>
    {
        response.Content.Headers.LastModified = new DateTime(2018, 3, 9);
    })
    .Verifiable(); // Naturally we can use Moq methods as well

// Verify methods are provided matching the setup helpers
handler.VerifyAnyRequest(Times.Exactly(3));

//使用HttpClient发出的所有请求都会通过其处理程序的SendAsync（）进行模拟
var handler=newmock（）；
var client=handler.CreateClient（）；
//一个简单的示例，对于任何请求都返回404
handler.SetupAnyRequest（）
.ReturnsResponse（HttpStatusCode.NotFound）；
//将GET请求与返回json的端点匹配（默认为200 OK）
handler.SetupRequest（HttpMethod.Get）https://example.com/api/stuff")
.ReturnsResponse（JsonConvert.SerializeObject（模型），“应用程序/json”）；
//使用可选的配置操作在响应上设置其他标头
handler.SetupRequest（“https://example.com/api/stuff")
.ReturnsResponse（字节，配置：响应=>
{
response.Content.Headers.LastModified=新日期时间（2018年3月9日）；
})
.Verifiable（）；//当然，我们也可以使用最小起重量法
//验证是否提供了与设置帮助程序匹配的方法
handler.VerifyAnyRequest（Times.justice（3））；

有关更多信息，请查看作者的博客文章

var server = FluentMockServer.Start(/*server and port can be setup here*/);
server.Given(
      Request.Create()
      .WithPath("/").UsingPost()
   )
   .RespondWith(
       Response.Create()
       .WithStatusCode(200)
       .WithHeader("Content-Type", "application/json")
       .WithBody("{'attr':'value'}")
   );

// All requests made with HttpClient go through its handler's SendAsync() which we mock
var handler = new Mock<HttpMessageHandler>();
var client = handler.CreateClient();

// A simple example that returns 404 for any request
handler.SetupAnyRequest()
    .ReturnsResponse(HttpStatusCode.NotFound);

// Match GET requests to an endpoint that returns json (defaults to 200 OK)
handler.SetupRequest(HttpMethod.Get, "https://example.com/api/stuff")
    .ReturnsResponse(JsonConvert.SerializeObject(model), "application/json");

// Setting additional headers on the response using the optional configure action
handler.SetupRequest("https://example.com/api/stuff")
    .ReturnsResponse(bytes, configure: response =>
    {
        response.Content.Headers.LastModified = new DateTime(2018, 3, 9);
    })
    .Verifiable(); // Naturally we can use Moq methods as well

// Verify methods are provided matching the setup helpers
handler.VerifyAnyRequest(Times.Exactly(3));