测试含有HTTP上下文的业务逻辑，比如Cookie、URL中的QueryString
在平时的代码过程中，常常会和HTTP上下文HttpContext打交道，最常见的如request、response、cookie、querystring等，比如我们新的逻辑：
public class UserService
{
private IHttpContextAccessor _httpContextAccessor;
public UserService(IHttpContextAccessor httpContextAccessor)
{
_httpContextAccessor = httpContextAccessor;
}
public bool IsLogin()
{
return _httpContextAccessor.HttpContext.Request.Cookies["username"] != null;
}
}
这时如何测试呢？马丁福勒在他的大作《企业应用架构模式》中明确指出“测试桩”的概念，来应对这种情况。各种Mock框架应运而生。比如我最喜欢的Moq：
public class TestCookie
{
private UserService _service;
[SetUp]
public void Init()
{
var httpContextAccessorMock = new Mock<IHttpContextAccessor>();
httpContextAccessorMock.Setup(x => x.HttpContext.Request.Cookies["username"]).Returns("yubaolee");
var server = new TestServer(WebHost.CreateDefaultBuilder()
.ConfigureServices(u =>u.AddScoped(x =>httpContextAccessorMock.Object))
.UseStartup<Startup>());
_service = server.Host.Services.GetService<UserService>();
}
[Test]
public void TestLogin()
{
bool result = _service.IsLogin();
Assert.IsTrue(result);
}
}
测试一次HTTP请求
有时我们需要测试Mvc框架的模型绑定，看看一次客户端的请求是否能被正确解析，亦或者测试WebAPI入口的一些Filter AOP等是否被正确触发，这时就需要测试一次HTTP请求。从严格意义上来讲这种测试已经脱离的单元测试的范畴，属于集成测试。但这种测试代码可以节省我们大量的重复劳动。asp.net core中可以通过TestServer快速实现这种模拟：
public class TestHttpRequest
{
private TestServer _testServer;
[SetUp]
public void Init()
{
_testServer = new TestServer(WebHost.CreateDefaultBuilder().UseStartup<Startup>());
}
[Test]
public void TestLogin()
{
var client = _testServer.CreateClient();
var result = client.GetStringAsync("/api/values/checklogin?name=yubao&password=yubao");
Console.WriteLine(result.Result);
}
}