public class MyUnitTest

    {

        private IServiceCollection service;

        private readonly ITestOutputHelper output;

        public MyUnitTest(ITestOutputHelper tempOutput)

        {

            output = tempOutput;// new TestOutputHelper();

            service = new ServiceCollection();

            service.AddmyMiddleware();

            service.BuildServiceProvider();

        }

        [Fact]

        public void test()

        {

        }

        [Fact]

        public void WritLine()

        {

            output.WriteLine("hi");

        }

    }