具有多个请求的模拟 HttpClient

问题描述 投票：0回答：6

我正在尝试对调用 API 的函数进行单元测试。我已经使用模拟 

HttpMessageHandler
成功完成了此操作，如下所示，它允许我伪造来自 API 的响应：

private static Mock<HttpMessageHandler> GetMockHttpMessageHandler(string mockResponse)
{
    var mockMessageHandler = new Mock<HttpMessageHandler>();
    mockMessageHandler.Protected()
        .Setup<Task<HttpResponseMessage>>("SendAsync", ItExpr.IsAny<HttpRequestMessage>(), ItExpr.IsAny<CancellationToken>())
        .Returns(Task.FromResult(new HttpResponseMessage
        {
            StatusCode = HttpStatusCode.OK,
            Content = new StringContent(mockResponse)
        }));
    return mockMessageHandler;
}

到目前为止，一切都很好。我已经能够测试一半的函数，后半部分进行另一个 api 调用 - 然后两个响应都被包装到系统使用的对象中。问题是，第二个 api 需要有不同的模拟响应。

我以为我可以将上面代码中的 

ItExpr.IsAny<HttpRequestMessage>()
更改为 
new HttpRequestMessage(HttpMethod.Post, "http://LiveUrl.com/AuthenticateUserCredential")
，然后有多个 
Setup/Returns
，响应根据 URI 进行更改，但我尝试如下（只有一个 
Setup/Return
为了测试我没有打破前半部分测试）

private static Mock<HttpMessageHandler> GetMockHttpMessageHandler(string mockResponse)
{
    var mockMessageHandler = new Mock<HttpMessageHandler>();
    mockMessageHandler.Protected()
        .Setup<Task<HttpResponseMessage>>("SendAsync", new HttpRequestMessage(HttpMethod.Post, "http://LiveUrl.com/AuthenticateUserCredential"), ItExpr.IsAny<CancellationToken>())
        .Returns(Task.FromResult(new HttpResponseMessage
        {
            StatusCode = HttpStatusCode.OK,
            Content = new StringContent(mockResponse)
        }));

    return mockMessageHandler;
}

现在上面的内容破坏了第一个 api 调用 - 我得到以下响应：

处理程序未返回响应消息

现在我陷入了困境 - 我想做的事情可能吗？

c# httpclient moq
6个回答
10
投票

认为在Moq中使用SetupSequence可以解决这个问题：

private HttpClient GetHttpClientWithHttpMessageHandlerSequenceResponseMock(List<Tuple<HttpStatusCode,HttpContent>> returns)
    {

        var handlerMock = new Mock<HttpMessageHandler>(MockBehavior.Strict);
        var handlerPart = handlerMock
           .Protected()
           // Setup the PROTECTED method to mock
           .SetupSequence<Task<HttpResponseMessage>>(
              "SendAsync",
              ItExpr.IsAny<HttpRequestMessage>(),
              ItExpr.IsAny<CancellationToken>()
           );

        foreach (var item in returns)
        {
            handlerPart = AddReturnPart(handlerPart,item.Item1,item.Item2);
        }
        handlerMock.Verify();
        // use real http client with mocked handler here
        var httpClient = new HttpClient(handlerMock.Object)
        {
            BaseAddress = new Uri("http://test.com/"),
        };
        return httpClient;
    }

    private Moq.Language.ISetupSequentialResult<Task<HttpResponseMessage>> AdddReturnPart(Moq.Language.ISetupSequentialResult<Task<HttpResponseMessage>> handlerPart,
        HttpStatusCode statusCode, HttpContent content)
    {
        return handlerPart

           // prepare the expected response of the mocked http call
           .ReturnsAsync(new HttpResponseMessage()
           {
               StatusCode = statusCode, // HttpStatusCode.Unauthorized,
               Content = content //new StringContent("[{'id':1,'value':'1'}]"),
           });
    }

调用上面的代码：

public void ExceuteMultipleHttpCalls()
{
            var contentSequence1 = new StringContent("{ 'id':'anId','email':'[email protected]'}", Encoding.UTF8, "application/json");
            var contentSequence2 = new StringContent("{ 'id':'anotherId','email':'[email protected]'}", Encoding.UTF8, "application/json");

            var sequenceResponse = new List<Tuple<HttpStatusCode, HttpContent>>
            {
                new Tuple<HttpStatusCode, HttpContent>(HttpStatusCode.OK, contentSequence1),
                new Tuple<HttpStatusCode, HttpContent>(HttpStatusCode.Created, contentSequence2)
            };

            HttpClient httpClient = GetHttpClientWithHttpMessageHandlerSequenceResponseMock(sequenceResponse);
//use this httpClient to call function where this client is called multiple times.

}

1
投票

调用 API 的函数无法进行单元测试，这不是单元测试，而是集成测试。 如果你想简化你的生活，请开始以实用的方式思考。

你有一个调用 API 的函数，假设它看起来像这样：

public string DoSomething()
{
    string myData = //here we call another API
    //here we do something with the response from the API
}

现在，在函数之外进行 API 调用：

string myData = // api call
DoSomething(myData);

public string DoSomething(string myData)
    {
        // here we do something with myData 
        //this function no longer cares how it got the data.
    }

现在您可以对您的功能进行单元测试，并且可以检查实际功能和业务规则，而不必担心模拟任何内容。一切都变得简单多了。

您仍然可以通过集成测试来测试实际的 API，这些测试将检查您是否返回正确的 HTTP 代码、异常、模型验证是否正确等。

1
投票

你可以这样做：

    var requestUri = "http://LiveUrl.com/AuthenticateUserCredential";

    var response = Task.FromResult(new HttpResponseMessage
    {
        StatusCode = HttpStatusCode.OK,
        Content = new StringContent(mockResponse)
    })

    mockMessageHandler
        .Protected()
        .Setup<Task<HttpResponseMessage>>("SendAsync", 
            ItExpr.Is<HttpRequestMessage>(x => x.RequestUri.AbsoluteUri.StartsWith(requestUri)),
            ItExpr.IsAny<CancellationToken>())
        .ReturnsAsync(response);
1
投票

对于那些感兴趣的人，模拟多个 HTTP 请求的 NSubstitute 版本将如下所示：

    var requestUri = "http://LiveUrl.com/AuthenticateUserCredential";
    
    var response = Task.FromResult(new HttpResponseMessage
    {
        StatusCode = HttpStatusCode.OK,
        Content = new StringContent(mockResponse)
    });
    var mockClient = Substitute.For<HttpClient>();
    
    mockClient.SendAsync(
        Arg.Is<HttpRequestMessage>(x => x.RequestUri.AbsoluteUri.StartsWith(requestUri)),
        Arg.Any<CancellationToken>())
       .Returns(response);
1
投票

不确定以前的版本是否不允许这样做，但是如果您在同一方法中有不同的 HTTP 调用，您可以通过指定 HttpRequestMessage 来对每个调用进行 Moq，与您所做的类似。与您的代码的唯一区别是不是将其初始化为新的

new HttpRequestMessage()

将其添加为

ItExpr.Is<HttpRequestMessage>(PREDICATE BY WHICH YOU WILL MATCH YOUR ROUTE)

例如：

private static Mock<HttpMessageHandler> GetMockHttpMessageHandler(string mockResponse)
{
    var mockMessageHandler = new Mock<HttpMessageHandler>();
    mockMessageHandler.Protected()
        .Setup<Task<HttpResponseMessage>>(
"SendAsync", 
//BELOW IS PREDICATE
 ItExpr.Is<HttpRequestMessage>(match => 
match.Method == HttpMethod.Post && match.RequestUri == "http://LiveUrl.com/AuthenticateUserCredential"), 
//END OF PREDICATE
ItExpr.IsAny<CancellationToken>())
        .Returns(Task.FromResult(new HttpResponseMessage
        {
            StatusCode = HttpStatusCode.OK,
            Content = new StringContent(mockResponse)
        }));

    return mockMessageHandler;
}

然后您可以在该设置下方添加另一个设置以使用不同的 URL 或使用不同的 HTTP 方法

0
投票

使用 RichardSzalay.MockHttp 库

var mockHttp = new MockHttpMessageHandler();
mockHttp
    .When("http://localhost/api/user/*")
    .Respond("application/json", "{'name' : 'Test McGee'}");
var client = mockHttp.ToHttpClient(); // pass this to your SUT

如果您对 HttpClient 进行了大量测试，无论如何您最终都会以 helper utils 的形式“重新发明”它

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