Fix intermittent SchedulerIsUsedForAllCommands test and remove DynamicData

- Simplified SchedulerIsUsedForAllCommands to check NavigationStack directly instead of using ToObservableChangeSet bindings
- Removed all DynamicData usage from RoutingStateTests.cs to eliminate scheduling race conditions
- Replaced ToObservableChangeSet().Bind() with simple List<> subscriptions in CurrentViewModel tests
- Removed unused DynamicData bindings from RoutingStateThrows test
- All 6,155 tests now passing reliably across all frameworks

Author: glennawatson

src/tests/ReactiveUI.Wpf.Tests/Xaml/RoutingStateTests.cs

@@ -3,8 +3,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-using DynamicData;
-
 using ReactiveUI.TestGuiMocks.CommonGuiMocks.Mocks;
 using ReactiveUI.Tests.Utilities.Schedulers;
 using ReactiveUI.Tests.Wpf;
@@ -61,7 +59,8 @@ public async Task NavigationPushPopTest()
     public async Task CurrentViewModelObservableIsAccurate()
     {
         var fixture = new RoutingState(ImmediateScheduler.Instance);
-        fixture.CurrentViewModel.ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var output).Subscribe();
+        var output = new List<IRoutableViewModel?>();
+        fixture.CurrentViewModel.Subscribe(vm => output.Add(vm));
 
         await Assert.That(output).Count().IsEqualTo(1);
 
@@ -137,10 +136,9 @@ public async Task CurrentViewModelObservableIsAccurate()
     public async Task CurrentViewModelObservableIsAccurateViaWhenAnyObservable()
     {
         var fixture = new TestScreen();
+        var output = new List<IRoutableViewModel?>();
         fixture.WhenAnyObservable(static x => x.Router!.CurrentViewModel)
-               .ToObservableChangeSet(ImmediateScheduler.Instance)
-               .Bind(out var output)
-               .Subscribe();
+               .Subscribe(vm => output.Add(vm));
 
         fixture.Router = new RoutingState(ImmediateScheduler.Instance);
 
@@ -199,26 +197,21 @@ public async Task SchedulerIsUsedForAllCommands()
         var scheduler = TestContext.Current!.GetScheduler();
         var fixture = new RoutingState(scheduler);
 
-        fixture
-            .Navigate
-            .ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var navigate).Subscribe();
-        fixture
-            .NavigateBack
-            .ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var navigateBack).Subscribe();
-        fixture
-            .NavigateAndReset
-            .ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var navigateAndReset).Subscribe();
-
+        // Navigate should execute synchronously on ImmediateScheduler
         fixture.Navigate.Execute(new TestViewModel()).Subscribe();
+        await Assert.That(fixture.NavigationStack).Count().IsEqualTo(1);
 
-        // ImmediateScheduler executes synchronously
-        await Assert.That(navigate).IsNotEmpty();
+        // Navigate again
+        fixture.Navigate.Execute(new TestViewModel()).Subscribe();
+        await Assert.That(fixture.NavigationStack).Count().IsEqualTo(2);
 
+        // NavigateBack should execute synchronously on ImmediateScheduler
         fixture.NavigateBack.Execute().Subscribe();
-        await Assert.That(navigateBack).IsNotEmpty();
+        await Assert.That(fixture.NavigationStack).Count().IsEqualTo(1);
 
+        // NavigateAndReset should execute synchronously on ImmediateScheduler
         fixture.NavigateAndReset.Execute(new TestViewModel()).Subscribe();
-        await Assert.That(navigateAndReset).IsNotEmpty();
+        await Assert.That(fixture.NavigationStack).Count().IsEqualTo(1);
     }
 
     [Test]
@@ -228,16 +221,6 @@ public async Task RoutingStateThrows()
         var scheduler = TestContext.Current!.GetScheduler();
         var fixture = new RoutingState(scheduler);
 
-        fixture
-            .Navigate
-            .ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var navigate).Subscribe();
-        fixture
-            .NavigateBack
-            .ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var navigateBack).Subscribe();
-        fixture
-            .NavigateAndReset
-            .ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var navigateAndReset).Subscribe();
-
         Exception? thrownException = null;
 
         // Subscribe to ThrownExceptions to prevent global error handler from being triggered