我正在尝试弄清楚如何将 FakeItEasy 与 HttpClient 一起使用，给出以下代码：
public Foo(string key, HttpClient httpClient = null)
{ .. }
public void DoGet()
{
....
if (_httpClient == null)
{
_httpClient = new HttpClient();
}
var response = _httpClient.GetAsync("user/1);
}
public void DoPost(foo Foo)
{
if (_httpClient == null)
{
_httpClient = new HttpClient();
}
var formData = new Dictionary<string, string>
{
{"Name", "Joe smith"},
{"Age", "40"}
};
var response = _httpClient.PostAsync("user",
new FormUrlEncodedContent(formData));
}
所以我不确定如何使用
FakeItEasyGetAsyncPostAsync生产代码不会传入 HttpClient，但单元测试将传入由 FakeItEasy 制作的假实例。
例如。
[Fact]
public void GivenBlah_DoGet_DoesSomething()
{
// Arrange.
var httpClient A.Fake<HttpClient>(); // <-- need help here.
var foo = new Foo("aa", httpClient);
// Act.
foo.DoGet();
// Assert....
}
我发现 FiE（以及大多数模拟包）适用于接口或虚拟方法。因此，对于这个问题，让我们假装，
GetAsyncPostAsync这是我的（或多或少）通用的 FakeHttpMessageHandler。
public class FakeHttpMessageHandler : HttpMessageHandler
{
private HttpResponseMessage _response;
public static HttpMessageHandler GetHttpMessageHandler( string content, HttpStatusCode httpStatusCode )
{
var memStream = new MemoryStream();
var sw = new StreamWriter( memStream );
sw.Write( content );
sw.Flush();
memStream.Position = 0;
var httpContent = new StreamContent( memStream );
var response = new HttpResponseMessage()
{
StatusCode = httpStatusCode,
Content = httpContent
};
var messageHandler = new FakeHttpMessageHandler( response );
return messageHandler;
}
public FakeHttpMessageHandler( HttpResponseMessage response )
{
_response = response;
}
protected override Task<HttpResponseMessage> SendAsync( HttpRequestMessage request, CancellationToken cancellationToken )
{
var tcs = new TaskCompletionSource<HttpResponseMessage>();
tcs.SetResult( _response );
return tcs.Task;
}
}
这是我的一个测试中使用的示例，该测试需要一些 JSON 作为返回值。
const string json = "{\"success\": true}";
var messageHandler = FakeHttpMessageHandler.GetHttpMessageHandler(
json, HttpStatusCode.BadRequest );
var httpClient = new HttpClient( messageHandler );
您现在可以将
httpClientGetAsyncmessageHandler您还可以创建一个
AbstractHandlerpublic abstract class AbstractHandler : HttpClientHandler
{
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
return Task.FromResult(SendAsync(request.Method, request.RequestUri.AbsoluteUri));
}
public abstract HttpResponseMessage SendAsync(HttpMethod method, string url);
}
然后您可以拦截对
AbstractHandler.SendAsync(HttpMethod method, string url)// Arrange
var httpMessageHandler = A.Fake<AbstractHandler>(options => options.CallsBaseMethods());
A.CallTo(() => httpMessageHandler.SendAsync(A<HttpMethod>._, A<string>._)).Returns(new HttpResponseMessage(HttpStatusCode.OK) { Content = new StringContent("Result")});
var httpClient = new HttpClient(httpMessageHandler);
// Act
var result = await httpClient.GetAsync("https://google.com/");
// Assert
Assert.Equal("Result", await result.Content.ReadAsStringAsync());
A.CallTo(() => httpMessageHandler.SendAsync(A<HttpMethod>._, "https://google.com/")).MustHaveHappenedOnceExactly();
更多信息可以在此博客上找到：https://www.meziantou.net/mocking-an-httpclient-using-an-httpclienthandler.htm
当我需要与 Gravatar 服务交互时，我做了类似的事情。我尝试使用 fakes/mocks，但发现使用 HttpClient 是不可能的。相反，我想出了一个自定义的 HttpMessageHandler 类，它可以让我预先加载预期的响应，大致如下：
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
namespace Tigra.Gravatar.LogFetcher.Specifications
{
/// <summary>
/// Class LoggingHttpMessageHandler.
/// Provides a fake HttpMessageHandler that can be injected into HttpClient.
/// The class requires a ready-made response message to be passed in the constructor,
/// which is simply returned when requested. Additionally, the web request is logged in the
/// RequestMessage property for later examination.
/// </summary>
public class LoggingHttpMessageHandler : DelegatingHandler
{
internal HttpResponseMessage ResponseMessage { get; private set; }
internal HttpRequestMessage RequestMessage { get; private set; }
public LoggingHttpMessageHandler(HttpResponseMessage responseMessage)
{
ResponseMessage = responseMessage;
}
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
CancellationToken cancellationToken)
{
RequestMessage = request;
return Task.FromResult(ResponseMessage);
}
}
}
然后我的测试上下文设置是这样的：
public class with_fake_gravatar_web_service
{
Establish context = () =>
{
MessageHandler = new LoggingHttpMessageHandler(new HttpResponseMessage(HttpStatusCode.OK));
GravatarClient = new HttpClient(MessageHandler);
Filesystem = A.Fake<FakeFileSystemWrapper>();
Fetcher = new GravatarFetcher(Committers, GravatarClient, Filesystem);
};
protected static LoggingHttpMessageHandler MessageHandler;
protected static HttpClient GravatarClient;
protected static FakeFileSystemWrapper Filesystem;
}
然后，这是使用它的测试（规范）的示例：
[Subject(typeof(GravatarFetcher), "Web service")]
public class when_fetching_imagaes_from_gravatar_web_service : with_fake_gravatar_web_service
{
Because of = () =>
{
var result = Fetcher.FetchGravatars(@"c:\"); // This makes the web request
Task.WaitAll(result.ToArray());
//"http://www.gravatar.com/avatar/".md5_hex(lc $email)."?d=404&size=".$size;
UriPath = MessageHandler.RequestMessage.RequestUri.GetComponents(UriComponents.Path, UriFormat.Unescaped);
};
It should_make_request_from_gravatar_dot_com =
() => MessageHandler.RequestMessage.RequestUri.Host.ShouldEqual("www.gravatar.com");
It should_make_a_get_request = () => MessageHandler.RequestMessage.Method.ShouldEqual(HttpMethod.Get);
// see https://en.gravatar.com/site/check/[email protected]
It should_request_the_gravatar_hash_for_tim_long =
() => UriPath.ShouldStartWith("avatar/df0478426c0e47cc5e557d5391e5255d");
static string UriPath;
}
您可以在 http://stash.teamserver.tigranetworks.co.uk/users/timlong/repos/tigra.gravatar.logfetcher/browse
查看完整源代码FakeItEasy 与大多数模拟库一样，不会为非抽象组件创建代理。对于
HttpClientGetAsyncPostAsyncvirtualabstract在这种情况下，您需要一个不同的抽象作为依赖项 -
HttpClient这并没有直接回答你的问题，但我不久前写了一个库，它提供了一个用于存根请求/响应的 API。它非常灵活，支持有序/无序匹配以及针对不匹配请求的可定制回退系统。
可以在 GitHub 上找到：https://github.com/richardszalay/mockhttp