如何在 ASP.NET 5 / MVC 6 的单元测试中访问 HttpContext

Question

假设我在中间件的 http 上下文中设置了一个值。例如 HttpContext.User。

如何在我的单元测试中测试 http 上下文。这是我正在尝试做的一个例子

中间件

public class MyAuthMiddleware
{
    private readonly RequestDelegate _next;

    public MyAuthMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task Invoke(HttpContext context)
    {
        context.User = SetUser(); 
        await next(context);
    }
}

测试

[Fact]
public async Task UserShouldBeAuthenticated()
{
    var server = TestServer.Create((app) => 
    {
        app.UseMiddleware<MyAuthMiddleware>();
    });

    using(server)
    {
        var response = await server.CreateClient().GetAsync("/");
        // After calling the middleware I want to assert that 
        // the user in the HttpContext was set correctly
        // but how can I access the HttpContext here?
    }
}

Answer 1

以下是您可以使用的两种方法：

// Directly test the middleware itself without setting up the pipeline
[Fact]
public async Task Approach1()
{
    // Arrange
    var httpContext = new DefaultHttpContext();
    var authMiddleware = new MyAuthMiddleware(next: (innerHttpContext) => Task.FromResult(0));

    // Act
    await authMiddleware.Invoke(httpContext);

    // Assert
    // Note that the User property on DefaultHttpContext is never null and so do
    // specific checks for the contents of the principal (ex: claims)
    Assert.NotNull(httpContext.User);
    var claims = httpContext.User.Claims;
    //todo: verify the claims
}

[Fact]
public async Task Approach2()
{
    // Arrange
    var server = TestServer.Create((app) =>
    {
        app.UseMiddleware<MyAuthMiddleware>();

        app.Run(async (httpContext) =>
        {
            if(httpContext.User != null)
            {
                await httpContext.Response.WriteAsync("Claims: "
                    + string.Join(
                        ",",
                        httpContext.User.Claims.Select(claim => string.Format("{0}:{1}", claim.Type, claim.Value))));
            }
        });
    });

    using (server)
    {
        // Act
        var response = await server.CreateClient().GetAsync("/");

        // Assert
        var actual = await response.Content.ReadAsStringAsync();
        Assert.Equal("Claims: ClaimType1:ClaimType1-value", actual);
    }
}

Answer 2

asp.net 5/MVC6 的 RC1 版本可以在单元测试中手动设置 HttpContext，太棒了！

        DemoController demoController = new DemoController();
        demoController.ActionContext = new ActionContext();
        demoController.ActionContext.HttpContext = new DefaultHttpContext();
        demoController.HttpContext.Session = new DummySession();

DefaultHttpContext 类由平台提供。 DummySession 可以只是实现 ISession 类的简单类。这大大简化了事情，因为不再需要模拟。

Answer 3

如果您将中间件类与其余代码隔离开来进行单元测试会更好。

由于HttpContext 类是一个抽象类，您可以使用类似Moq 的模拟框架（将"Moq": "4.2.1502.911", 作为依赖项添加到您的project.json 文件中）来验证用户属性是否已设置。

例如，您可以编写以下测试来验证您的中间件 Invoke 函数是否在 httpContext 中设置 User 属性并调用下一个中间件：

[Fact]
public void MyAuthMiddleware_SetsUserAndCallsNextDelegate()
{
    //Arrange
    var httpContextMock = new Mock<HttpContext>()
            .SetupAllProperties();
    var delegateMock = new Mock<RequestDelegate>();
    var sut = new MyAuthMiddleware(delegateMock.Object);

    //Act
    sut.Invoke(httpContextMock.Object).Wait();

    //Assert
    httpContextMock.VerifySet(c => c.User = It.IsAny<ClaimsPrincipal>(), Times.Once);
    delegateMock.Verify(next => next(httpContextMock.Object), Times.Once);
}

然后您可以编写额外的测试来验证用户是否具有预期值，因为您将能够使用httpContextMock.Object.User 获取设置的用户对象：

Assert.NotNull(httpContextMock.Object.User);
//additional validation, like user claims, id, name, roles

Answer 4

看看这篇文章：

Setting HttpContext.Current.Session in a unit test

我想你需要的是这个。

public static HttpContext FakeHttpContext(string url)
{
    var uri = new Uri(url);
    var httpRequest = new HttpRequest(string.Empty, uri.ToString(),
                                        uri.Query.TrimStart('?'));
    var stringWriter = new StringWriter();
    var httpResponse = new HttpResponse(stringWriter);
    var httpContext = new HttpContext(httpRequest, httpResponse);

    var sessionContainer = new HttpSessionStateContainer("id",
                                    new SessionStateItemCollection(),
                                    new HttpStaticObjectsCollection(),
                                    10, true, HttpCookieMode.AutoDetect,
                                    SessionStateMode.InProc, false);

    SessionStateUtility.AddHttpSessionStateToContext(
                                         httpContext, sessionContainer);

    return httpContext;
}

然后你可以像这样使用它：

request.SetupGet(req => req.Headers).Returns(new NameValueCollection());
HttpContextFactory.Current.Request.Headers.Add(key, value);