src/Lucene.Net.Tests/Support/Util/Events/TestBackgroundEventSubscription.cs

// Source: https://github.com/PrismLibrary/Prism/blob/7f0b1680bbe754da790274f80851265f808d9bbf

#region Copyright .NET Foundation, Licensed under the MIT License (MIT)
// The MIT License (MIT)
//
// Copyright(c).NET Foundation
//
// All rights reserved. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
// documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
// IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#endregion

#if !FEATURE_CONDITIONALWEAKTABLE_ENUMERATOR

using NUnit.Framework;
using System;
using System.Threading;
using Assert = Lucene.Net.TestFramework.Assert;

namespace Lucene.Net.Util.Events
{
    [TestFixture]
    public class TestBackgroundEventSubscription
    {
        [Test]
        public void ShouldReceiveDelegateOnDifferentThread()
        {
            ManualResetEvent completeEvent = new ManualResetEvent(false);
            SynchronizationContext.SetSynchronizationContext(new SynchronizationContext());
            SynchronizationContext calledSyncContext = null;
            Action<object> action = delegate
            {
                calledSyncContext = SynchronizationContext.Current;
                completeEvent.Set();
            };

            IDelegateReference actionDelegateReference = new MockDelegateReference() { Target = action };
            IDelegateReference filterDelegateReference = new MockDelegateReference() { Target = (Predicate<object>)delegate { return true; } };

            var eventSubscription = new BackgroundEventSubscription<object>(actionDelegateReference, filterDelegateReference);


            var publishAction = eventSubscription.GetExecutionStrategy();

            Assert.NotNull(publishAction);

            publishAction.Invoke(null);

            completeEvent.WaitOne(5000);

            Assert.AreNotEqual(SynchronizationContext.Current, calledSyncContext);
        }

        [Test]
        public void ShouldReceiveDelegateOnDifferentThreadNonGeneric()
        {
            var completeEvent = new ManualResetEvent(false);
            SynchronizationContext.SetSynchronizationContext(new SynchronizationContext());
            SynchronizationContext calledSyncContext = null;
            Action action = delegate
            {
                calledSyncContext = SynchronizationContext.Current;
                completeEvent.Set();
            };

            IDelegateReference actionDelegateReference = new MockDelegateReference() { Target = action };

            var eventSubscription = new BackgroundEventSubscription(actionDelegateReference);

            var publishAction = eventSubscription.GetExecutionStrategy();

            Assert.NotNull(publishAction);

            publishAction.Invoke(null);

            completeEvent.WaitOne(5000);

            Assert.AreNotEqual(SynchronizationContext.Current, calledSyncContext);
        }
    }
}

#endif