BackgroundService正在阻止WebApplicationFactory.CreateClient在集成测试中的完成

Question

我们正在使用SpecFlow为.net-core-3.1 WebApplication编写集成测试。我们的网络应用程序包括一个用于订阅卡夫卡的BackgroundService。这个BackgroundService的存在阻止了WebApplicationFactory.CreateClient方法的完成。我读过一些人在资源有限的测试环境中遇到了类似的问题，但这种情况发生在现代笔记本电脑上。

我们的测试类的构造函数：

public PocServiceSteps(ScenarioContext context)
{
    _context = context;

    _factory = new WebApplicationFactory<Startup>()
    .WithWebHostBuilder(builder => builder.ConfigureServices(services =>
    {
        // setup any required services changes here
    }));

    // this method never completes
    _client = _factory.CreateClient(
        new WebApplicationFactoryClientOptions
        {
            BaseAddress = new Uri($"http://localhost:5000/")
        }
    );
}

我们尝试过的一件事是重写每个https://www.strathweb.com/2021/05/the-curious-case-of-asp-net-core-integration-test-deadlock/的https://www.strathweb.com/2021/05/the-curious-case-of-asp-net-core-integration-test-deadlock/，但这并不能解决问题：

private class AsyncFriendlyWebApplicationFactory<T> : WebApplicationFactory<T> where T : class
{
    protected override IHost CreateHost(IHostBuilder builder)
    {
        var host = builder.Build();
        Task.Run(() => host.StartAsync()).GetAwaiter().GetResult();
        return host;
    }
}

Answer 1

如果测试不需要后台服务，只需删除它：

var factory = new WebApplicationFactory<Startup>()
    .WithWebHostBuilder(builder =>
        builder.ConfigureTestServices(s =>
        {
            var descriptor = s.SingleOrDefault(
                d => d.ImplementationType ==
                     typeof(MyBackgroundService));

            s.Remove(descriptor);
        })
    );

如果您像这样在Startup.cs中注册了您的服务：

builder.Services.AddHostedService<MyBackgroundService>();