我有一些问题,试图包装我的代码在单元测试中使用。问题在于。我有接口IHttpHandler:
public interface IHttpHandler
{
HttpClient client { get; }
}
使用它的类HttpHandler:
public class HttpHandler : IHttpHandler
{
public HttpClient client
{
get
{
return new HttpClient();
}
}
}
然后是Connection类,它使用simpleIOC注入客户端实现:
public class Connection
{
private IHttpHandler _httpClient;
public Connection(IHttpHandler httpClient)
{
_httpClient = httpClient;
}
}
然后我有一个单元测试项目,它有这个类:
private IHttpHandler _httpClient;
[TestMethod]
public void TestMockConnection()
{
var client = new Connection(_httpClient);
client.doSomething();
// Here I want to somehow create a mock instance of the http client
// Instead of the real one. How Should I approach this?
}
现在很明显,我将在Connection类中拥有从后端检索数据(JSON)的方法。但是,我想为这个类编写单元测试,显然我不想针对真正的后端编写测试,而是一个模拟的后端。我试着给这个问题一个好的答案,但没有成功。我以前可以用Moq来模拟,但从来没有在HttpClient这样的东西上使用过。我应该如何处理这个问题?
我的一个同事注意到,大多数HttpClient方法都在底层调用SendAsync(HttpRequestMessage request, CancellationToken CancellationToken),这是HttpMessageInvoker的一个虚拟方法:
所以到目前为止,模拟HttpClient最简单的方法就是简单地模拟这个特定的方法:
var mockClient = new Mock<HttpClient>();
mockClient.Setup(client => client.SendAsync(It.IsAny<HttpRequestMessage>(), It.IsAny<CancellationToken>())).ReturnsAsync(_mockResponse.Object);
并且您的代码可以调用大多数(但不是全部)HttpClient类方法,包括常规方法
httpClient.SendAsync(req)
点击这里确认
https://github.com/dotnet/corefx/blob/master/src/System.Net.Http/src/System/Net/Http/HttpClient.cs
微软现在提供了使用IHttpClientFactory而不是直接使用HttpClient的替代方案:
https://learn.microsoft.com/en-us/aspnet/core/fundamentals/http-requests?view=aspnetcore-5.0
使用返回预期结果的请求进行模拟:
private LoginController GetLoginController()
{
var expected = "Hello world";
var mockFactory = new Mock<IHttpClientFactory>();
var mockMessageHandler = new Mock<HttpMessageHandler>();
mockMessageHandler.Protected()
.Setup<Task<HttpResponseMessage>>("SendAsync", ItExpr.IsAny<HttpRequestMessage>(), ItExpr.IsAny<CancellationToken>())
.ReturnsAsync(new HttpResponseMessage
{
StatusCode = HttpStatusCode.OK,
Content = new StringContent(expected)
});
var httpClient = new HttpClient(mockMessageHandler.Object);
mockFactory.Setup(_ => _.CreateClient(It.IsAny<string>())).Returns(httpClient);
var logger = Mock.Of<ILogger<LoginController>>();
var controller = new LoginController(logger, mockFactory.Object);
return controller;
}
来源:
https://stackoverflow.com/a/66256132/3850405
也许在您当前的项目中会有一些代码需要更改,但对于新项目,您绝对应该考虑使用Flurl。
https://flurl.dev
它是一个。net的HTTP客户端库,具有一个流畅的接口,特别支持使用它来发出HTTP请求的代码的可测试性。
网站上有很多代码示例,但简单地说,你在代码中是这样使用的。
添加用途。
using Flurl;
using Flurl.Http;
发送get请求并读取响应。
public async Task SendGetRequest()
{
var response = await "https://example.com".GetAsync();
// ...
}
在单元测试中,Flurl充当一个模拟,可以将其配置为所需的行为,还可以验证所执行的调用。
using (var httpTest = new HttpTest())
{
// Arrange
httpTest.RespondWith("OK", 200);
// Act
await sut.SendGetRequest();
// Assert
httpTest.ShouldHaveCalled("https://example.com")
.WithVerb(HttpMethod.Get);
}
HttpClient的可扩展性在于传递给构造函数的HttpMessageHandler。它的目的是允许特定于平台的实现,但您也可以模拟它。不需要为HttpClient创建装饰器包装。
如果你更喜欢DSL而不是使用Moq,我在GitHub/Nuget上有一个库,它可以让事情变得更容易一些:https://github.com/richardszalay/mockhttp
Nuget包RichardSzalay。MockHttp可以在这里找到。
var mockHttp = new MockHttpMessageHandler();
// Setup a respond for the user api (including a wildcard in the URL)
mockHttp.When("http://localhost/api/user/*")
.Respond("application/json", "{'name' : 'Test McGee'}"); // Respond with JSON
// Inject the handler or client into your application code
var client = new HttpClient(mockHttp);
var response = await client.GetAsync("http://localhost/api/user/1234");
// or without async: var response = client.GetAsync("http://localhost/api/user/1234").Result;
var json = await response.Content.ReadAsStringAsync();
// No network connection required
Console.Write(json); // {'name' : 'Test McGee'}
正如注释中提到的,您需要抽象HttpClient,这样就不会与它耦合。我以前也做过类似的事情。我会试着把我的方法和你们要做的方法相适应。
首先看一下HttpClient类,并决定需要它提供哪些功能。
以下是一种可能性:
public interface IHttpClient {
System.Threading.Tasks.Task<T> DeleteAsync<T>(string uri) where T : class;
System.Threading.Tasks.Task<T> DeleteAsync<T>(Uri uri) where T : class;
System.Threading.Tasks.Task<T> GetAsync<T>(string uri) where T : class;
System.Threading.Tasks.Task<T> GetAsync<T>(Uri uri) where T : class;
System.Threading.Tasks.Task<T> PostAsync<T>(string uri, object package);
System.Threading.Tasks.Task<T> PostAsync<T>(Uri uri, object package);
System.Threading.Tasks.Task<T> PutAsync<T>(string uri, object package);
System.Threading.Tasks.Task<T> PutAsync<T>(Uri uri, object package);
}
如前所述,这是为了特定目的。我完全抽象出了对HttpClient的依赖,并专注于我想要返回的东西。您应该评估如何抽象HttpClient以只提供您想要的必要功能。
这将允许您只模拟需要测试的内容。
我甚至建议完全放弃IHttpHandler,而使用HttpClient抽象IHttpClient。但我只是没有选择,因为你可以用抽象客户端的成员替换你的处理程序接口的主体。
IHttpClient的实现可以用来包装/改编一个真正的/具体的HttpClient或任何其他对象,它可以用来发出HTTP请求,因为你真正想要的是一个服务,它提供了与HttpClient相反的功能。使用抽象是一种干净(我的观点)和可靠的方法,并且可以使您的代码更易于维护,如果您需要在框架更改时将底层客户端切换为其他东西。
下面是如何实现的代码片段。
/// <summary>
/// HTTP Client adaptor wraps a <see cref="System.Net.Http.HttpClient"/>
/// that contains a reference to <see cref="ConfigurableMessageHandler"/>
/// </summary>
public sealed class HttpClientAdaptor : IHttpClient {
HttpClient httpClient;
public HttpClientAdaptor(IHttpClientFactory httpClientFactory) {
httpClient = httpClientFactory.CreateHttpClient(**Custom configurations**);
}
//...other code
/// <summary>
/// Send a GET request to the specified Uri as an asynchronous operation.
/// </summary>
/// <typeparam name="T">Response type</typeparam>
/// <param name="uri">The Uri the request is sent to</param>
/// <returns></returns>
public async System.Threading.Tasks.Task<T> GetAsync<T>(Uri uri) where T : class {
var result = default(T);
//Try to get content as T
try {
//send request and get the response
var response = await httpClient.GetAsync(uri).ConfigureAwait(false);
//if there is content in response to deserialize
if (response.Content.Headers.ContentLength.GetValueOrDefault() > 0) {
//get the content
string responseBodyAsText = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
//desrialize it
result = deserializeJsonToObject<T>(responseBodyAsText);
}
} catch (Exception ex) {
Log.Error(ex);
}
return result;
}
//...other code
}
正如你在上面的例子中所看到的,很多通常与使用HttpClient相关的繁重工作都隐藏在抽象后面。
然后可以用抽象客户端注入连接类
public class Connection
{
private IHttpClient _httpClient;
public Connection(IHttpClient httpClient)
{
_httpClient = httpClient;
}
}
然后,您的测试可以模拟SUT所需的内容
private IHttpClient _httpClient;
[TestMethod]
public void TestMockConnection()
{
SomeModelObject model = new SomeModelObject();
var httpClientMock = new Mock<IHttpClient>();
httpClientMock.Setup(c => c.GetAsync<SomeModelObject>(It.IsAny<string>()))
.Returns(() => Task.FromResult(model));
_httpClient = httpClientMock.Object;
var client = new Connection(_httpClient);
// Assuming doSomething uses the client to make
// a request for a model of type SomeModelObject
client.doSomething();
}