NullReferenceException in TestScheduler

[mattpodwysocki]

NullReferenceException in TestScheduler

[mattpodwysocki]

I posted some repro code on this stackoverflow query http://stackoverflow.com/questions/26287710

Code also posted below...

    using Microsoft.Reactive.Testing;
    using Microsoft.VisualStudio.TestTools.UnitTesting;
    using System;
    using System.Reactive.Linq;
    using System.Threading;

    namespace UnitTestProject1
    {
    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public void TestBackgroundThreadWithTestScheduler()
        {
            var scheduler = new TestScheduler();
            var seq = Observable.Never<string>();

            bool subscribed = false;
            ThreadPool.QueueUserWorkItem(_ =>
            {
                Thread.Sleep(100); //wait a bit to give main thread chance to start advancing scheduler
                seq.Timeout(TimeSpan.FromSeconds(10), scheduler)
                   .Subscribe(s => {/*never called*/});
                subscribed = true; //signal we're subscribed
            });

            //----  Uncommenting this line to avoid the race condition appears to fix the test ----
            //while (!subscribed) Thread.Yield(); 

            //Advance the scheduer in small increments to maximise our chances of hitting the race
            var watch = scheduler.StartStopwatch();
            try
            {
                while (watch.Elapsed < TimeSpan.FromSeconds(20)) scheduler.AdvanceBy(10);
            }
            //NullReference is thrown unexpectedly
            catch (NullReferenceException ex)
            {
                Assert.Fail("Virtual time {0}, exception {1}", watch.Elapsed, ex);
            }
            catch (TimeoutException)
            {
                //desired result is a TimeoutException so this is a test pass
            }
        }
    }
    }

[bartdesmet]

This has now been fixed by making VirtualTimeScheduler thread-safe.