Multi threaded test

    [TestClass]
    public class SomeTest
    {
        [TestMethod]
        public void Test_threaded_code()
        {
            var db = new SomeDbMock();
            var bl = new SomeCode(db);

            bl.DoSomething();

            Assert.IsTrue(TestHelper.Run(() => db.TextSaved == "Hello World!", 500), "Text never became Hello World!");
        }
    }

    public class TestHelper
    {
        public static bool Run(Func<bool> check, int timeout)
        {
            var sw = new Stopwatch();
            sw.Start();

            while(true)
            {
                if (sw.ElapsedMilliseconds > timeout)
                    return false;

                if (check()) return true;
            }
        }
    }

    public class SomeDbMock
    {
        public string TextSaved;

        public void SaveText(string text)
        {
            TextSaved = text;
        }
    }

    public class SomeCode
    {
        private SomeDbMock _db;

        public SomeCode(SomeDbMock mock)
        {
            _db = mock;   
        }

        public void DoSomething()
        {
            var t = new Thread(DoSomethingOnThread);
            t.Start();
        }

        private void DoSomethingOnThread()
        {
            Thread.Sleep(250);
            _db.SaveText("Hello World!");   
        }
    }