c# - 单元测试在 System.Net.Http v4 中使用 HttpClient 的类

Question

我想对下面使用 HttpClient 的搜索类进行单元测试，

public class Search:ISearch{
HttpClient httpClient;
  public Search(HttpClient httpClient){
   this.httpClient = httpClient;
}
   //use httClient to send request.
}

有没有办法模拟 HttpClient？我无法通过 Google 找到任何信息。

更新

除了发送可以模拟的 Http Web 请求之外，是否有替代方案。我有以下代码:

 public class Search:ISearch{
private static readonly string url = "http://www.google.com/search";
public Result SendSearch(string query){
           string queryUrl = string.Format("{0}?q={1}", url, query);
           var webRequest = WebRequest.Create(queryUrl);
          ///...
}

Answer 1

在 .Net 4.5 框架中，您可以执行此操作。

public class FakeHttpMessageHandler : HttpMessageHandler
{
    private HttpResponseMessage response;

    public FakeHttpMessageHandler(HttpResponseMessage response)
    {
        this.response = response;
    }

    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var responseTask =  new TaskCompletionSource<HttpResponseMessage>();
        responseTask.SetResult(response);

        return responseTask.Task;
    }
}


[TestMethod]
public void TestGetContents()
{
    var responseMessage = new HttpResponseMessage();
    var messageHandler = new FakeHttpMessageHandler(responseMessage);
    var client = new HttpClient(messageHandler);
    var sut = new Search(client);

    sut.SendSearch("urQuery");

    // Asserts
}