[TestClass]
    public static class TestHostBuild
    {
        public static HttpClient GetTestClient() => _host.GetTestClient();

        [AssemblyInitialize]
        public static async Task GlobalInitialize(TestContext testContext)
        {
            IHost host = await CreateAndRun();
            _host = host;
        }

        private static IHost _host;

        [AssemblyCleanup]
        public static void GlobalCleanup()
        {
            _host.Dispose();
        }

        private static Task<IHost> CreateAndRun() => CreateHostBuilder().StartAsync();

        public static IHostBuilder CreateHostBuilder() =>
            Host.CreateDefaultBuilder()
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                    webBuilder.UseTestServer(); //关键是多了这一行建立TestServer
                })
                .ConfigureAppConfiguration((hostingContext, config) =>
                {
                	// 进行测试的配置
                    var appConfigurator = config.ToAppConfigurator();
                    // 这里使用了 https://github.com/dotnet-campus/dotnetCampus.Configurations 做配置
                    var apmConfiguration = appConfigurator.Of<ApmConfiguration>();
                    apmConfiguration.DisableApm = true;
                })
                // 使用 auto fac 代替默认的 IOC 容器 
                .UseServiceProviderFactory(new AutofacServiceProviderFactory());
               
    }

    [ApiController]
    [Route("[controller]")]
    [Route("/")]
    public class StatusOverviewController : ControllerBase
    {
    	[HttpGet]
        public string Get()
        {
        	// 也许使用 DateTimeOffset 更清真，但这又不是我写的
        	return DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
        }
    }

    [TestClass]
    public class StatusOverviewControllerTest
    {
        [TestMethod]
        public async Task GetTest()
        {
            using var httpClient = TestHostBuild.GetTestClient();

            var result = await httpClient.GetStringAsync("/");
            Assert.IsNotNull(result);
        }
    }

[TestClass]
public class DemoTest
{
    [ContractTestCase]
    public void Foo()
    {
        "当满足 A 条件时，应该发生 A' 事。".Test(() =>
        {
            // Arrange
            // Action
            // Assert
        });
        
        "当满足 B 条件时，应该发生 B' 事。".Test(() =>
        {
            // Arrange
            // Action
            // Assert
        });
    }
}