Simplify handler GC tests

src/Core/tests/DeviceTests/Memory/MemoryTestFixture.cs

@@ -1,13 +1,11 @@
 using System;
 using System.Collections.Generic;
 
-
 namespace Microsoft.Maui.Handlers.Memory
 {
 	public class MemoryTestFixture : IDisposable
 	{
-		Dictionary<Type, (WeakReference handler, WeakReference view)> _handlers
-			= new Dictionary<Type, (WeakReference handler, WeakReference view)>();
+		readonly Dictionary<Type, (WeakReference handler, WeakReference view)> _handlers = new();
 
 		public MemoryTestFixture()
 		{
@@ -20,24 +18,14 @@ public MemoryTestFixture()
 
 		public bool DoReferencesStillExist(Type handlerType)
 		{
-			WeakReference weakHandler;
-			WeakReference weakView;
-			(weakHandler, weakView) = _handlers[handlerType];
-
-
-			if (weakHandler.Target != null ||
-				weakHandler.IsAlive ||
-				weakView.Target != null ||
-				weakView.IsAlive)
-			{
-				return true;
-			}
+			(WeakReference weakHandler, WeakReference  weakView) = _handlers[handlerType];
 
-			return false;
+			return weakHandler.IsAlive || weakView.IsAlive;
 		}
 
 		public void Dispose()
 		{
+			GC.SuppressFinalize(this);
 			_handlers.Clear();
 		}
 	}

src/Core/tests/DeviceTests/Memory/MemoryTests.cs

@@ -1,21 +1,9 @@
 using System;
-using System.Collections;
-using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Maui.DeviceTests;
-using Microsoft.Maui.DeviceTests.Stubs;
-using Microsoft.Maui.Graphics;
-using Microsoft.Maui.Media;
 using Xunit;
-using Xunit.Abstractions;
-using Xunit.Sdk;
 using static Microsoft.Maui.DeviceTests.AssertHelpers;
 
-
 namespace Microsoft.Maui.Handlers.Memory
 {
 	/// <summary>
@@ -35,52 +23,41 @@ public MemoryTests(MemoryTestFixture fixture)
 			_fixture = fixture;
 		}
 
-		[Theory]
-		[ClassData(typeof(MemoryTestTypes))]
-		public async Task Allocate((Type ViewType, Type HandlerType) data)
+		async Task Allocate((Type ViewType, Type HandlerType) data)
 		{
-
-#if ANDROID
-			if (!OperatingSystem.IsAndroidVersionAtLeast(30))
-				return;
-#endif
-
 			var handler = await InvokeOnMainThreadAsync(() => CreateHandler((IElement)Activator.CreateInstance(data.ViewType), data.HandlerType));
-			WeakReference weakHandler = new WeakReference(handler);
-			_fixture.AddReferences(data.HandlerType, (weakHandler, new WeakReference(handler.VirtualView)));
-			handler = null;
+			var view = handler.VirtualView;
 
-			GC.Collect();
-			GC.WaitForPendingFinalizers();
-			GC.Collect();
-			GC.WaitForPendingFinalizers();
+			WeakReference weakHandlerReference = new WeakReference(handler);
+			WeakReference weakViewReference = new WeakReference(view);
+
+			_fixture.AddReferences(data.HandlerType, (weakHandlerReference, weakViewReference));
 		}
 
 		[Theory]
 		[ClassData(typeof(MemoryTestTypes))]
 		public async Task CheckAllocation((Type ViewType, Type HandlerType) data)
 		{
+			// Arrange
+			await Allocate(data);
 
-#if ANDROID
-			if (!OperatingSystem.IsAndroidVersionAtLeast(30))
-				return;
-#endif
-
-			// This is mainly relevant when running inside the visual runner as a single test
-			if (!_fixture.HasType(data.HandlerType))
-				await Allocate(data);
-
-			bool referencesCollected()
+			async Task<bool> referencesCollected()
 			{
-				GC.Collect();
-				GC.WaitForPendingFinalizers();
-				GC.Collect();
-				GC.WaitForPendingFinalizers();
+				// Act
+				await Collect();
 
+				// Assert
 				return !_fixture.DoReferencesStillExist(data.HandlerType);
 			}
 
 			await AssertEventually(referencesCollected, timeout: 5000, message: $"{data.HandlerType} failed to collect.");
 		}
+
+		static async Task Collect()
+		{
+			await Task.Yield();
+			GC.Collect();
+			GC.WaitForPendingFinalizers();
+		}
 	}
 }

src/TestUtils/src/DeviceTests/AssertHelpers.cs

@@ -27,6 +27,27 @@ public static async Task AssertEventually(Func<bool> assertion, int timeout = 10
 			}
 		}
 
+		public static async Task AssertEventually(Func<Task<bool>> assertion, int timeout = 1000, int interval = 100, string message = "Assertion timed out")
+		{
+			do
+			{
+				if (await assertion())
+				{
+					return;
+				}
+
+				await Task.Delay(interval);
+				timeout -= interval;
+
+			}
+			while (timeout >= 0);
+
+			if (! (await assertion()))
+			{
+				throw new XunitException(message);
+			}
+		}
+
 		public static async Task<bool> Wait(Func<bool> predicate, int timeout = 1000, int interval = 100) 
 		{
 			do