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测试HttpModule wtih响应。过滤器和响应。写

moq integration-testing c#

Eonasdan · 技术社区 · 8 年前

我正在开发一个Http模块,它只记录响应时间和大小,然后将结果附加到响应正文中。

我的模块如下所示:

public override void PreRequestHandlerExecute(HttpContextBase context)
{
    // Add a filter to capture response stream
    context.Response.Filter = new ResponseSniffer(context.Response.Filter);
}

public override void ApplicationEndRequest(HttpContextBase context)
{
    ....
    context.Response.Write(builder.ToString());
}

现在我想对这个模块进行单元测试。我对单元测试非常陌生。我改编了 o2platform 获取moq httpcontext,到目前为止,这是可行的。然而,响应过滤器似乎是在Pre中设置的,响应主体是我从测试设置中初始化的。

我尝试了几个选项(并阅读了很多资料),但这些选项似乎都不起作用:

public Mock<HttpResponseBase> MockResponse { get; set; }
...
var outputStream = new MemoryStream();
var filter = new MemoryStream();

//MockResponse.Setup(response => response.OutputStream).Returns(GetMockStream(outputStream).Object);
//MockResponse.Setup(response => response.Filter).Returns(GetMockStream(filter).Object);

MockResponse.Setup(response => response.OutputStream).Returns(() => outputStream);
//MockResponse.SetupSet(response => response.OutputStream = It.IsAny<Stream>()).Returns(() => outputStream);

MockResponse.Setup(response => response.Filter).Returns(() => filter);
MockResponse.SetupSet(response => response.Filter = It.IsAny<Stream>());
MockResponse.SetupSet(response => response.Filter = It.IsAny<ResponseSniffer>());

试验方法

[TestMethod]
public void TestMethod1()
{
    var mockHttpContext = new MoqHttpContext();

    var httpContext = mockHttpContext.HttpContext();
    var html = @"<html>
                    <head></head>
                    <body>
                        <h1>Hello World</h1>
                    </body>
                </html>";

    httpContext.ResponseWrite(html);
    httpContext.StreamWrite(httpContext.Response.Filter, html);


    var module = new Module();

    module.PreRequestHandlerExecute(mockHttpContext.HttpContext());
    module.ApplicationBeginRequest(mockHttpContext.HttpContext());
    module.ApplicationEndRequest(mockHttpContext.HttpContext());

    var responseRead = httpContext.ResponseRead(); //extension method to get output stream
    var b = 1; //put breakpoint here
}

我意识到测试需要断言,而不是断点。我也意识到考试应该分一下。

代码回购

Github

1 回复 | 直到 8 年前

CodeFuller 8 年前

让我们看看中的以下语句 Module.ApplicationEndRequest() 方法:

context.Response.Write(builder.ToString());

当从单元测试执行此代码时, context.Response 是您在MoqHttpContext中设置的模拟。CreateBaseMocks():

MockResponse = new Mock<HttpResponseBase>();
// ...
MockContext.Setup(ctx => ctx.Response).Returns(MockResponse.Object);

你不能指望你打电话给 Write() 方法,然后可以读回相同的数据。Mock是一个伪对象。其默认实现 写入() 方法不执行任何操作,传递的数据将丢失。

要解决此问题,可以在上设置回调 Response mock,将传递的数据写入流,然后在读取时返回。实际上你离它很近。

在里面 MoqHttpContext 类声明将在其中保存数据的流:

public class MoqHttpContext
{
    private readonly MemoryStream _outputStream = new MemoryStream();

    // ...
}

然后在 CreateBaseMocks() 方法设置回调:

public MoqHttpContext CreateBaseMocks()
{
    // ...

    MockResponse = new Mock<HttpResponseBase>();
    MockResponse.Setup(x => x.Write(It.IsAny<string>())).Callback<string>(s =>
    {
        var data = Encoding.ASCII.GetBytes(s);
        _outputStream.Write(data, 0, data.Length);
        _outputStream.Flush();
        _outputStream.Position = 0;
    });

    // ...
}

还应删除设置 inputStream 定位到 0 在里面 MoqHttpContextExtensions.StreamWrite() ,以便您写入的html数据 UnitTest1.TestMethod1() 追加,而不是覆盖:

public static HttpContextBase StreamWrite(this HttpContextBase httpContextBase, Stream inputStream, string text)
{
    if (inputStream == null) inputStream = new MemoryStream();
    var streamWriter = new StreamWriter(inputStream);

    inputStream.Position = inputStream.Length;
    streamWriter.Write(text);
    streamWriter.Flush();
    // Remove this line
    //inputStream.Position = 0;

    return httpContextBase;
}

就是这样。现在,如果您检查 responseRead 在测试中,您将看到Http模块附加的数据就在那里。

更新 (修复过滤器问题)

当前代码有3个不同的问题会妨碍UT过滤器的正确工作。

你尝试了几个嘲弄的选项 Filter 然而,它们似乎都不正确。使用Moq模拟属性getter的正确方法是:
```
MockResponse.SetupGet(response => response.Filter).Returns(filter);
```
删除所有其他模拟语句 response.Filter ,但暂时不要添加上述声明,这还不是最终版本。
您有以下签入 单元ApplicationEndRequest() 方法:
```
if (context.Response.Filter is ResponseSniffer filter)
{
    // ...
```
执行UT时, context.Response.Filter 是一个 MemoryStream 不是一个 ResponseSniffer . 调用的Setter Module 建造商:
```
context.Response.Filter = new ResponseSniffer(context.Response.Filter);
```
实际上不会影响返回的值 滤器 getter,因为它是一个模拟,当前总是返回 内存流 安装时使用的 SetupGet . 要解决此问题,您应该实际模拟属性行为:保存传递给setter的值并在getter中返回它。以下是的最终设置 回答滤器 属性:
```
Stream filter = new MemoryStream();
MockResponse.SetupSet(response => response.Filter = It.IsAny<Stream>()).Callback<Stream>(value => filter = value);
MockResponse.SetupGet(response => response.Filter).Returns(() => filter);
```
确保已删除的所有其他模拟 回答滤器 所有物

您应该解决的最后一个问题是 单元 来自UT的调用。目前的顺序如下:

httpContext.StreamWrite(httpContext.Response.Filter, html);
// ...
var module = new Module();
module.PreRequestHandlerExecute(mockHttpContext.HttpContext());

但是 PreRequestHandlerExecute 集合 Response.Filter 以实例 响应Sniffer . 那么什么时候 httpContext.StreamWrite 上面叫做, httpContext.Response.Filter 实际持有的实例 内存流 不 响应Sniffer . 因此,您应该做的最后一个修复是更改UT正文中语句的顺序:

// ...

var module = new Module();
module.PreRequestHandlerExecute(mockHttpContext.HttpContext());

httpContext.ResponseWrite(html);
httpContext.StreamWrite(httpContext.Response.Filter, html);

module.ApplicationBeginRequest(mockHttpContext.HttpContext());
module.ApplicationEndRequest(mockHttpContext.HttpContext());

// ...

更新 (UT重新设计)

此时,您的UT应该可以工作。然而,当前的测试非常繁琐。事实证明,要花这么多时间才能理解为什么它不起作用。这样的测试很难维护和修复,随着时间的推移,它们会成为一种真正的痛苦。

此外,它更像是集成测试而不是单元测试,因为它调用了几个具有不同功能的类- 响应Sniffer 和 单元 .

您应该强烈考虑重新设计当前测试。好的开始是对 响应Sniffer 和 单元 课程。

最有价值的测试 响应Sniffer 用于验证写入数据是否已在中注册 RecordStream :

[TestClass]
public class ResponseSnifferTests
{
    [TestMethod]
    public void Write_WritesDataToRecordStream()
    {
        //  Arrange

        var inData = new byte[] { 0x01 };

        var target = new ResponseSniffer(Mock.Of<Stream>());

        //  Act

        target.Write(inData, 0, inData.Length);

        //  Assert

        target.RecordStream.Position = 0;
        var outData = new byte[inData.Length];
        int outSize = target.RecordStream.Read(outData, 0, outData.Length);
        Assert.AreEqual(inData.Length, outSize);
        CollectionAssert.AreEqual(inData, outData);
    }
}

关于 单元 类中,应进行以下几项检查:

PreRequestHandlerExecute() 集合 回答滤器 具有的实例 响应Sniffer .
ApplicationBeginRequest() 添加 Stopwatch 到 context.Items 词典
ApplicationEndRequest() 将请求信息写入响应。

UT方法意味着在单独的测试中检查这些事实。以下是这3项测试的样本:

[TestClass]
public class ModuleTests
{
    [TestMethod]
    public void PreRequestHandlerExecuteShouldSetResponseSnifferAsFilter()
    {
        //  Arrange

        Stream filter = null;
        Mock<HttpResponseBase> httpResponseMock = new Mock<HttpResponseBase>();
        httpResponseMock.SetupSet(response => response.Filter = It.IsAny<Stream>()).Callback<Stream>(value => filter = value);

        Mock<HttpContextBase> httpContextStub = new Mock<HttpContextBase>();
        httpContextStub.SetupGet(x => x.Response).Returns(httpResponseMock.Object);

        var target = new Module();

        //  Act

        target.PreRequestHandlerExecute(httpContextStub.Object);

        //  Assert

        Assert.IsNotNull(filter);
        Assert.IsInstanceOfType(filter, typeof(ResponseSniffer));
    }

    [TestMethod]
    public void ApplicationBeginRequestShouldStoreStopwatchInContextItems()
    {
        //  Arrange

        var items = new Dictionary<string, object>();

        Mock<HttpContextBase> httpContextStub = new Mock<HttpContextBase>();
        httpContextStub.SetupGet(x => x.Items).Returns(items);

        var target = new Module();

        //  Act

        target.ApplicationBeginRequest(httpContextStub.Object);

        //  Assert

        Assert.IsTrue(items.ContainsKey("X-ResponseTime"));
        Assert.IsInstanceOfType(items["X-ResponseTime"], typeof(Stopwatch));
    }

    [TestMethod]
    public void ApplicationEndRequestShouldAddRequestInfoToResponse()
    {
        //  Arrange

        Mock<HttpRequestBase> httpRequestMock = new Mock<HttpRequestBase>();
        httpRequestMock.SetupGet(x => x.FilePath).Returns("/test");

        string writtenData = null;
        Mock<HttpResponseBase> httpResponseMock = new Mock<HttpResponseBase>();
        httpResponseMock.Setup(x => x.Write(It.IsAny<string>())).Callback<string>(s => writtenData = s);

        Mock<HttpContextBase> httpContextStub = new Mock<HttpContextBase>();
        httpContextStub.SetupGet(x => x.Request).Returns(httpRequestMock.Object);
        httpContextStub.SetupGet(x => x.Response).Returns(httpResponseMock.Object);
        httpContextStub.SetupGet(x => x.Items).Returns(new Dictionary<string, object> { ["X-ResponseTime"] = new Stopwatch() });

        var target = new Module();

        //  Act

        target.ApplicationEndRequest(httpContextStub.Object);

        //  Assert

        Assert.IsTrue(Regex.IsMatch(writtenData, @"Response Size: \d+ bytes<br/>"));
        Assert.IsTrue(Regex.IsMatch(writtenData, @"Module request time: \d+ ms"));
    }
}

正如您所看到的,测试非常简单和直接。你不需要这些 MoqHttpContext 和 MoqHttpContextExtensions 还有很多嘲笑和帮助。另一个好处是,如果某些测试被破坏,则更容易确定根本原因并加以修复。

如果您是单元测试新手,并且正在寻找关于它的良好信息源,我强烈建议您阅读这本书 The Art of Unit Testing 罗伊·奥舍洛夫。