Unit Test mesajı görüntüleme

using System;
using System.Diagnostics;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Test.FMC.Turkiye.Wcf.EFatura.WCFInvoice;
using System.Windows.Forms;
namespace Test.FMC.Turkiye.Wcf.EFatura {
    [TestClass]
    public class FEInvoiceTest {
        public TestContext TestContext { get; set; }
        static FEInvoiceClient clnt = null;
        [TestInitialize]
        public void Initialize() { clnt = new WCFInvoice.FEInvoiceClient(); }

        [TestCleanup]
        public void Cleanup() { clnt.Close(); clnt = null; }

        [TestMethod]
        public void CreateFEInvoiceClient() {
            var sonuc = clnt.Hello();

            Debug.WriteLine($"Debug mesaj: {sonuc}");
            Console.WriteLine($"Console mesaj: {sonuc}");
            Trace.WriteLine($"Trace mesaj: {sonuc}");
            TestContext.WriteLine($"TestContext mesaj: {sonuc}");
            MessageBox.Show(sonuc);
            Assert.IsTrue(!string.IsNullOrEmpty(sonuc), "Hello çağırılamadı!");
        }
    }
}