Avalonia/tests/Avalonia.Base.UnitTests/DispatcherTests.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Avalonia.Controls.Platform;
using Avalonia.Threading;
using Avalonia.Utilities;
using Xunit;
namespace Avalonia.Base.UnitTests;

public partial class DispatcherTests
{
    class SimpleDispatcherImpl : IDispatcherImpl, IDispatcherImplWithPendingInput
    {
        private readonly Thread _loopThread = Thread.CurrentThread;
        private readonly object _lock = new();
        public bool CurrentThreadIsLoopThread => Thread.CurrentThread == _loopThread;
        public void Signal()
        {
            lock (_lock)
                AskedForSignal = true;
        }

        public event Action Signaled;
        public event Action Timer;
        public long? NextTimer { get; private set; }
        public bool AskedForSignal { get; private set; }

        public void UpdateTimer(long? dueTimeInTicks)
        {
            NextTimer = dueTimeInTicks;
        }

        public long Now { get; set; }

        public void ExecuteSignal()
        {
            lock (_lock)
            {
                if (!AskedForSignal)
                    return;
                AskedForSignal = false;
            }
            Signaled?.Invoke();
        }

        public void ExecuteTimer()
        {
            if (NextTimer == null)
                return;
            Now = NextTimer.Value;
            Timer?.Invoke();
        }

        public bool CanQueryPendingInput => TestInputPending != null;
        public bool HasPendingInput => TestInputPending == true;
        public bool? TestInputPending { get; set; }
    }

    class SimpleDispatcherWithBackgroundProcessingImpl : SimpleDispatcherImpl, IDispatcherImplWithExplicitBackgroundProcessing
    {
        public bool AskedForBackgroundProcessing { get; private set; }
        public event Action ReadyForBackgroundProcessing;
        public void RequestBackgroundProcessing()
        {
            if (!CurrentThreadIsLoopThread)
                throw new InvalidOperationException();
            AskedForBackgroundProcessing = true;
        }

        public void FireBackgroundProcessing()
        {
            if(!AskedForBackgroundProcessing)
                return;
            AskedForBackgroundProcessing = false;
            ReadyForBackgroundProcessing?.Invoke();
        }
    }

    class SimpleControlledDispatcherImpl : SimpleDispatcherWithBackgroundProcessingImpl, IControlledDispatcherImpl
    {
        private readonly bool _useTestTimeout = true;
        private readonly CancellationToken? _cancel;
        public int RunLoopCount { get; private set; }

        public SimpleControlledDispatcherImpl()
        {

        }

        public SimpleControlledDispatcherImpl(CancellationToken cancel, bool useTestTimeout = false)
        {
            _useTestTimeout = useTestTimeout;
            _cancel = cancel;
        }

        public void RunLoop(CancellationToken token)
        {
            RunLoopCount++;
            var st = Stopwatch.StartNew();
            while (!token.IsCancellationRequested || _cancel?.IsCancellationRequested == true)
            {
                FireBackgroundProcessing();
                ExecuteSignal();
                if (_useTestTimeout)
                    Assert.True(st.ElapsedMilliseconds < 4000, "RunLoop exceeded test time quota");
                else
                    Thread.Sleep(10);
            }
        }


    }


    [Fact]
    public void DispatcherExecutesJobsAccordingToPriority()
    {
        var impl = new SimpleDispatcherImpl();
        var disp = new Dispatcher(impl);
        var actions = new List<string>();
        disp.Post(()=>actions.Add("Background"), DispatcherPriority.Background);
        disp.Post(()=>actions.Add("Render"), DispatcherPriority.Render);
        disp.Post(()=>actions.Add("Input"), DispatcherPriority.Input);
        Assert.True(impl.AskedForSignal);
        impl.ExecuteSignal();
        Assert.Equal(new[] { "Render", "Input", "Background" }, actions);
    }

    [Fact]
    public void DispatcherPreservesOrderWhenChangingPriority()
    {
        var impl = new SimpleDispatcherImpl();
        var disp = new Dispatcher(impl);
        var actions = new List<string>();
        var toPromote = disp.InvokeAsync(()=>actions.Add("PromotedRender"), DispatcherPriority.Background);
        var toPromote2 = disp.InvokeAsync(()=>actions.Add("PromotedRender2"), DispatcherPriority.Input);
        disp.Post(() => actions.Add("Render"), DispatcherPriority.Render);

        toPromote.Priority = DispatcherPriority.Render;
        toPromote2.Priority = DispatcherPriority.Render;

        Assert.True(impl.AskedForSignal);
        impl.ExecuteSignal();

        Assert.Equal(new[] { "PromotedRender", "PromotedRender2", "Render" }, actions);
    }

    [Fact]
    public void DispatcherStopsItemProcessingWhenInteractivityDeadlineIsReached()
    {
        var impl = new SimpleDispatcherImpl();
        var disp = new Dispatcher(impl);
        var actions = new List<int>();
        for (var c = 0; c < 10; c++)
        {
            var itemId = c;
            disp.Post(() =>
            {
                actions.Add(itemId);
                impl.Now += 20;
            }, DispatcherPriority.Background);
        }

        Assert.False(impl.AskedForSignal);
        Assert.NotNull(impl.NextTimer);

        for (var c = 0; c < 4; c++)
        {
            Assert.NotNull(impl.NextTimer);
            Assert.False(impl.AskedForSignal);
            impl.ExecuteTimer();
            Assert.False(impl.AskedForSignal);
            impl.ExecuteSignal();
            var expectedCount = (c + 1) * 3;
            if (c == 3)
                expectedCount = 10;

            Assert.Equal(Enumerable.Range(0, expectedCount), actions);
            Assert.False(impl.AskedForSignal);
            if (c < 3)
            {
                Assert.True(impl.NextTimer > impl.Now);
            }
            else
                Assert.Null(impl.NextTimer);
        }
    }


    [Fact]
    public void DispatcherStopsItemProcessingWhenInputIsPending()
    {
        var impl = new SimpleDispatcherImpl();
        impl.TestInputPending = true;
        var disp = new Dispatcher(impl);
        var actions = new List<int>();
        for (var c = 0; c < 10; c++)
        {
            var itemId = c;
            disp.Post(() =>
            {
                actions.Add(itemId);
                if (itemId == 0 || itemId == 3 || itemId == 7)
                    impl.TestInputPending = true;
            }, DispatcherPriority.Background);
        }
        Assert.False(impl.AskedForSignal);
        Assert.NotNull(impl.NextTimer);
        impl.TestInputPending = false;

        for (var c = 0; c < 4; c++)
        {
            Assert.NotNull(impl.NextTimer);
            impl.ExecuteTimer();
            Assert.False(impl.AskedForSignal);
            var expectedCount = c switch
            {
                0 => 1,
                1 => 4,
                2 => 8,
                3 => 10,
                _ => throw new InvalidOperationException($"Unexpected value {c}")
            };

            Assert.Equal(Enumerable.Range(0, expectedCount), actions);
            Assert.False(impl.AskedForSignal);
            if (c < 3)
            {
                Assert.True(impl.NextTimer > impl.Now);
                impl.Now = impl.NextTimer.Value + 1;
            }
            else
                Assert.Null(impl.NextTimer);

            impl.TestInputPending = false;
        }
    }

    [Theory,
     InlineData(false, false),
     InlineData(false, true),
     InlineData(true, false),
     InlineData(true, true)]
    public void CanWaitForDispatcherOperationFromTheSameThread(bool controlled, bool foreground)
    {
        var impl = controlled ? new SimpleControlledDispatcherImpl() : new SimpleDispatcherImpl();
        var disp = new Dispatcher(impl);
        bool finished = false;

        disp.InvokeAsync(() => finished = true,
            foreground ? DispatcherPriority.Default : DispatcherPriority.Background).Wait();

        Assert.True(finished);
        if (controlled)
            Assert.Equal(foreground ? 0 : 1, ((SimpleControlledDispatcherImpl)impl).RunLoopCount);
    }


    class DispatcherServices : IDisposable
    {
        private readonly IDisposable _scope;

        public DispatcherServices(IDispatcherImpl impl)
        {
            _scope = AvaloniaLocator.EnterScope();
            AvaloniaLocator.CurrentMutable.Bind<IDispatcherImpl>().ToConstant(impl);
            Dispatcher.ResetForUnitTests();
            SynchronizationContext.SetSynchronizationContext(null);
        }

        public void Dispose()
        {
            Dispatcher.ResetForUnitTests();
            _scope.Dispose();
            SynchronizationContext.SetSynchronizationContext(null);
        }
    }

    [Fact]
    public void ExitAllFramesShouldExitAllFramesAndBeAbleToContinue()
    {
        using (new DispatcherServices(new SimpleControlledDispatcherImpl()))
        {
            var actions = new List<string>();
            var disp = Dispatcher.UIThread;
            disp.Post(() =>
            {
                actions.Add("Nested frame");
                Dispatcher.UIThread.MainLoop(CancellationToken.None);
                actions.Add("Nested frame exited");
            });
            disp.Post(() =>
            {
                actions.Add("ExitAllFrames");
                disp.ExitAllFrames();
            });


            disp.MainLoop(CancellationToken.None);

            Assert.Equal(new[] { "Nested frame", "ExitAllFrames", "Nested frame exited" }, actions);
            actions.Clear();

            var secondLoop = new CancellationTokenSource();
            disp.Post(() =>
            {
                actions.Add("Callback after exit");
                secondLoop.Cancel();
            });
            disp.MainLoop(secondLoop.Token);
            Assert.Equal(new[] { "Callback after exit" }, actions);
        }
    }


    [Fact]
    public void ShutdownShouldExitAllFramesAndNotAllowNewFrames()
    {
        using (new DispatcherServices(new SimpleControlledDispatcherImpl()))
        {
            var actions = new List<string>();
            var disp = Dispatcher.UIThread;
            disp.Post(() =>
            {
                actions.Add("Nested frame");
                Dispatcher.UIThread.MainLoop(CancellationToken.None);
                actions.Add("Nested frame exited");
            });
            disp.Post(() =>
            {
                actions.Add("Shutdown");
                disp.BeginInvokeShutdown(DispatcherPriority.Normal);
            });

            disp.Post(() =>
            {
                actions.Add("Nested frame after shutdown");
                // This should exit immediately and not run any jobs
                Dispatcher.UIThread.MainLoop(CancellationToken.None);
                actions.Add("Nested frame after shutdown exited");
            });

            var criticalFrameAfterShutdown = new DispatcherFrame(false);
            disp.Post(() =>
            {
                actions.Add("Critical frame after shutdown");

                Dispatcher.UIThread.PushFrame(criticalFrameAfterShutdown);
                actions.Add("Critical frame after shutdown exited");
            });
            disp.Post(() =>
            {
                actions.Add("Stop critical frame");
                criticalFrameAfterShutdown.Continue = false;
            });

            disp.MainLoop(CancellationToken.None);

            Assert.Equal(new[]
            {
                "Nested frame",
                "Shutdown",
                // Normal nested frames are supposed to exit immediately
                "Nested frame after shutdown", "Nested frame after shutdown exited",
                // if frame is configured to not answer dispatcher requests, it should be allowed to run
                "Critical frame after shutdown", "Stop critical frame", "Critical frame after shutdown exited",
                // After 3-rd level frames have exited, the normal nested frame exits too
                "Nested frame exited"
            }, actions);
            actions.Clear();

            disp.Post(()=>actions.Add("Frame after shutdown finished"));
            Assert.Throws<InvalidOperationException>(() => disp.MainLoop(CancellationToken.None));
            Assert.Empty(actions);
        }
    }

    class WaitHelper : SynchronizationContext, NonPumpingLockHelper.IHelperImpl
    {
        public int WaitCount;
        public override int Wait(IntPtr[] waitHandles, bool waitAll, int millisecondsTimeout)
        {
            WaitCount++;
            return base.Wait(waitHandles, waitAll, millisecondsTimeout);
        }
    }

    [Fact]
    public void DisableProcessingShouldStopProcessing()
    {
        using (new DispatcherServices(new SimpleControlledDispatcherImpl()))
        {
            var helper = new WaitHelper();
            AvaloniaLocator.CurrentMutable.Bind<NonPumpingLockHelper.IHelperImpl>().ToConstant(helper);
            using (Dispatcher.UIThread.DisableProcessing())
            {
                Assert.True(SynchronizationContext.Current is NonPumpingSyncContext);
                Assert.Throws<InvalidOperationException>(() => Dispatcher.UIThread.MainLoop(CancellationToken.None));
                Assert.Throws<InvalidOperationException>(() => Dispatcher.UIThread.RunJobs());
            }

            var avaloniaContext = new AvaloniaSynchronizationContext(Dispatcher.UIThread, DispatcherPriority.Default, true);
            SynchronizationContext.SetSynchronizationContext(avaloniaContext);

            var waitHandle = new ManualResetEvent(true);

            helper.WaitCount = 0;
            waitHandle.WaitOne(100);
            Assert.Equal(0, helper.WaitCount);
            using (Dispatcher.UIThread.DisableProcessing())
            {
                Assert.Equal(avaloniaContext, SynchronizationContext.Current);
                waitHandle.WaitOne(100);
                Assert.Equal(1, helper.WaitCount);
            }
        }
    }

    [Fact]
    public void DispatcherOperationsHaveContextWithProperPriority()
    {
        using (new DispatcherServices(new SimpleControlledDispatcherImpl()))
        {
            SynchronizationContext.SetSynchronizationContext(null);
            var disp = Dispatcher.UIThread;
            var priorities = new List<DispatcherPriority>();

            void DumpCurrentPriority() =>
                priorities.Add(((AvaloniaSynchronizationContext)SynchronizationContext.Current!).Priority);


            disp.Post(DumpCurrentPriority, DispatcherPriority.Normal);
            disp.Post(DumpCurrentPriority, DispatcherPriority.Loaded);
            disp.Post(DumpCurrentPriority, DispatcherPriority.Input);
            disp.Post(() =>
            {
                DumpCurrentPriority();
                disp.ExitAllFrames();
            }, DispatcherPriority.Background);
            disp.MainLoop(CancellationToken.None);

            disp.Invoke(DumpCurrentPriority, DispatcherPriority.Send);
            disp.Invoke(() =>
            {
                DumpCurrentPriority();
                return 1;
            }, DispatcherPriority.Send);

            Assert.Equal(
                new[]
                {
                    DispatcherPriority.Normal, DispatcherPriority.Loaded, DispatcherPriority.Input, DispatcherPriority.Background,
                    DispatcherPriority.Send, DispatcherPriority.Send,
                },
                priorities);


        }
    }

    [Fact]
    [SuppressMessage("Usage", "xUnit1031:Do not use blocking task operations in test method", Justification = "Tests the dispatcher itself")]
    public void DispatcherInvokeAsyncUnwrapsTasks()
    {
        int asyncMethodStage = 0;

        async Task AsyncMethod()
        {
            asyncMethodStage = 1;
            await Task.Delay(200);
            asyncMethodStage = 2;
        }

        async Task<int> AsyncMethodWithResult()
        {
            await Task.Delay(100);
            return 1;
        }

        async Task Test()
        {
            await Dispatcher.UIThread.InvokeAsync(AsyncMethod);
            Assert.Equal(2, asyncMethodStage);
            Assert.Equal(1, await Dispatcher.UIThread.InvokeAsync(AsyncMethodWithResult));
            asyncMethodStage = 0;

            await Dispatcher.UIThread.InvokeAsync(AsyncMethod, DispatcherPriority.Default);
            Assert.Equal(2, asyncMethodStage);
            Assert.Equal(1, await Dispatcher.UIThread.InvokeAsync(AsyncMethodWithResult, DispatcherPriority.Default));

            Dispatcher.UIThread.ExitAllFrames();
        }

        using (new DispatcherServices(new ManagedDispatcherImpl(null)))
        {
            var t = Test();
            var cts = new CancellationTokenSource();
            Task.Delay(3000).ContinueWith(_ => cts.Cancel());
            Dispatcher.UIThread.MainLoop(cts.Token);
            Assert.True(t.IsCompletedSuccessfully);
            t.GetAwaiter().GetResult();
        }
    }


    [Fact]
    public async Task DispatcherResumeContinuesOnUIThread()
    {
        using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());

        var tokenSource = new CancellationTokenSource();
        var workload = Dispatcher.UIThread.InvokeAsync(
            async () =>
            {
                Assert.True(Dispatcher.UIThread.CheckAccess());

                await Task.Delay(1).ConfigureAwait(false);
                Assert.False(Dispatcher.UIThread.CheckAccess());

                await Dispatcher.UIThread.Resume();
                Assert.True(Dispatcher.UIThread.CheckAccess());

                tokenSource.Cancel();
            });

        Dispatcher.UIThread.MainLoop(tokenSource.Token);
    }

    [Fact]
    public async Task DispatcherYieldContinuesOnUIThread()
    {
        using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());

        var tokenSource = new CancellationTokenSource();
        var workload = Dispatcher.UIThread.InvokeAsync(
            async () =>
            {
                Assert.True(Dispatcher.UIThread.CheckAccess());

                await Dispatcher.Yield();
                Assert.True(Dispatcher.UIThread.CheckAccess());

                tokenSource.Cancel();
            });

        Dispatcher.UIThread.MainLoop(tokenSource.Token);
    }

    [Fact]
    public async Task DispatcherYieldThrowsOnNonUIThread()
    {
        using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());

        var tokenSource = new CancellationTokenSource();
        var workload = Dispatcher.UIThread.InvokeAsync(
            async () =>
            {
                Assert.True(Dispatcher.UIThread.CheckAccess());

                await Task.Delay(1).ConfigureAwait(false);
                Assert.False(Dispatcher.UIThread.CheckAccess());
                await Assert.ThrowsAsync<InvalidOperationException>(async () => await Dispatcher.Yield());

                tokenSource.Cancel();
            });

        Dispatcher.UIThread.MainLoop(tokenSource.Token);
    }

    [Fact]
    public async Task AwaitWithPriorityRunsOnUIThread()
    {
        static async Task<int> Workload()
        {
            await Task.Delay(1).ConfigureAwait(false);
            Assert.False(Dispatcher.UIThread.CheckAccess());

            return Thread.CurrentThread.ManagedThreadId;
        }

        using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());

        var tokenSource = new CancellationTokenSource();
        var workload = Dispatcher.UIThread.InvokeAsync(
            async () =>
            {
                Assert.True(Dispatcher.UIThread.CheckAccess());
                Task taskWithoutResult = Workload();

                await Dispatcher.UIThread.AwaitWithPriority(taskWithoutResult, DispatcherPriority.Default);

                Assert.True(Dispatcher.UIThread.CheckAccess());
                Task<int> taskWithResult = Workload();

                await Dispatcher.UIThread.AwaitWithPriority(taskWithResult, DispatcherPriority.Default);

                Assert.True(Dispatcher.UIThread.CheckAccess());

                tokenSource.Cancel();
            });

        Dispatcher.UIThread.MainLoop(tokenSource.Token);
    }

#nullable enable
    private class AsyncLocalTestClass
    {
        public AsyncLocal<string?> AsyncLocalField { get; set; } = new AsyncLocal<string?>();
    }

    [Fact]
    public async Task ExecutionContextIsPreservedInDispatcherInvokeAsync()
    {
        using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());
        var tokenSource = new CancellationTokenSource();
        string? test1 = null;
        string? test2 = null;
        string? test3 = null;

        // All test code must run inside Task.Run to avoid interfering with the test:
        //  1. Prevent the execution context from being captured by MainLoop.
        //  2. Prevent the execution context from remaining effective when set on the same thread.
        var task = Task.Run(() =>
        {
            var testObject = new AsyncLocalTestClass();

            // Test 1: Verify Task.Run preserves the execution context.
            // First, test Task.Run to ensure that the preceding validation always passes, serving as a baseline for the subsequent Invoke/InvokeAsync tests.
            // This way, if a later test fails, we have the .NET framework's baseline behavior for reference.
            testObject.AsyncLocalField.Value = "Initial Value";
            var task1 = Task.Run(() =>
            {
                test1 = testObject.AsyncLocalField.Value;
            });

            // Test 2: Verify Invoke preserves the execution context.
            testObject.AsyncLocalField.Value = "Initial Value";
            Dispatcher.UIThread.Invoke(() =>
            {
                test2 = testObject.AsyncLocalField.Value;
            });

            // Test 3: Verify InvokeAsync preserves the execution context.
            testObject.AsyncLocalField.Value = "Initial Value";
            _ = Dispatcher.UIThread.InvokeAsync(() =>
            {
                test3 = testObject.AsyncLocalField.Value;
            });

            _ = Dispatcher.UIThread.InvokeAsync(async () =>
            {
                await Task.WhenAll(task1);
                tokenSource.Cancel();
            });

        });

        Dispatcher.UIThread.MainLoop(tokenSource.Token);
        await Task.WhenAll(task);

        // Assertions
        // Task.Run: Always passes (guaranteed by the .NET runtime).
        Assert.Equal("Initial Value", test1);
        // Invoke: Always passes because the context is not changed.
        Assert.Equal("Initial Value", test2);
        // InvokeAsync: See https://github.com/AvaloniaUI/Avalonia/pull/19163
        Assert.Equal("Initial Value", test3);
    }

    [Fact]
    public async Task ExecutionContextIsNotPreservedAmongDispatcherInvokeAsync()
    {
        using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());
        var tokenSource = new CancellationTokenSource();
        string? test = null;

        // All test code must run inside Task.Run to avoid interfering with the test:
        //  1. Prevent the execution context from being captured by MainLoop.
        //  2. Prevent the execution context from remaining effective when set on the same thread.
        var task = Task.Run(() =>
        {
            var testObject = new AsyncLocalTestClass();

            // Test: Verify that InvokeAsync calls do not share execution context between each other.
            _ = Dispatcher.UIThread.InvokeAsync(() =>
            {
                testObject.AsyncLocalField.Value = "Initial Value";
            });
            _ = Dispatcher.UIThread.InvokeAsync(() =>
            {
                test = testObject.AsyncLocalField.Value;
            });

            _ = Dispatcher.UIThread.InvokeAsync(() =>
            {
                tokenSource.Cancel();
            });
        });

        Dispatcher.UIThread.MainLoop(tokenSource.Token);
        await Task.WhenAll(task);

        // Assertions
        // The value should NOT flow between different InvokeAsync execution contexts.
        Assert.Null(test);
    }

    [Fact]
    public async Task ExecutionContextCultureInfoIsPreservedInDispatcherInvokeAsync()
    {
        using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());
        var tokenSource = new CancellationTokenSource();
        string? test1 = null;
        string? test2 = null;
        string? test3 = null;
        var oldCulture = Thread.CurrentThread.CurrentCulture;

        // All test code must run inside Task.Run to avoid interfering with the test:
        //  1. Prevent the execution context from being captured by MainLoop.
        //  2. Prevent the execution context from remaining effective when set on the same thread.
        var task = Task.Run(() =>
        {
            // This culture tag is Sumerian and is extremely unlikely to be set as the default on any device,
            // ensuring that this test will not be affected by the user's environment.
            Thread.CurrentThread.CurrentCulture = CultureInfo.GetCultureInfo("sux-Shaw-UM");

            // Test 1: Verify Task.Run preserves the culture in the execution context.
            // First, test Task.Run to ensure that the preceding validation always passes, serving as a baseline for the subsequent Invoke/InvokeAsync tests.
            // This way, if a later test fails, we have the .NET framework's baseline behavior for reference.
            var task1 = Task.Run(() =>
            {
                test1 = Thread.CurrentThread.CurrentCulture.Name;
            });

            // Test 2: Verify Invoke preserves the execution context.
            Dispatcher.UIThread.Invoke(() =>
            {
                test2 = Thread.CurrentThread.CurrentCulture.Name;
            });

            // Test 3: Verify InvokeAsync preserves the culture in the execution context.
            _ = Dispatcher.UIThread.InvokeAsync(() =>
            {
                test3 = Thread.CurrentThread.CurrentCulture.Name;
            });

            _ = Dispatcher.UIThread.InvokeAsync(async () =>
            {
                await Task.WhenAll(task1);
                tokenSource.Cancel();
            });
        });

        try
        {
            Dispatcher.UIThread.MainLoop(tokenSource.Token);
            await Task.WhenAll(task);

            // Assertions
            // Task.Run: Always passes (guaranteed by the .NET runtime).
            Assert.Equal("sux-Shaw-UM", test1);
            // Invoke: Always passes because the context is not changed.
            Assert.Equal("sux-Shaw-UM", test2);
            // InvokeAsync: See https://github.com/AvaloniaUI/Avalonia/pull/19163
            Assert.Equal("sux-Shaw-UM", test3);
        }
        finally
        {
            Thread.CurrentThread.CurrentCulture = oldCulture;
            // Ensure that this test does not have a negative impact on other tests.
            Assert.NotEqual("sux-Shaw-UM", oldCulture.Name);
        }
    }
#nullable restore

}