[Testing] Replace Thread.Sleep with retryTimeout in UI tests

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue10563.cs

@@ -31,7 +31,9 @@ public void Issue10563OpenSwipeViewTest()
 			App.Tap(OpenLeftId);
 			// Wait for swipe animation to complete - the SwipeItem text becomes visible
 			App.WaitForElement("Issue 10563");
-			VerifyScreenshotOrSetException(ref exception, "Left_SwipeItems", retryTimeout: TimeSpan.FromSeconds(2));
+			// SwipeView animations can have timing variance - use retryTimeout (not tolerance)
+			// per UI testing guidelines which recommend retryTimeout for timing issues
+			VerifyScreenshotOrSetException(ref exception, "Left_SwipeItems", retryTimeout: TimeSpan.FromSeconds(3));
 			App.Tap(CloseId);
 			// Wait for close animation to complete - the SwipeItem text disappears
 			App.WaitForNoElement("Issue 10563");
@@ -40,23 +42,23 @@ public void Issue10563OpenSwipeViewTest()
 			App.WaitForElement(OpenRightId);
 			App.Tap(OpenRightId);
 			App.WaitForElement("Issue 10563");
-			VerifyScreenshotOrSetException(ref exception, "Right_SwipeItems", retryTimeout: TimeSpan.FromSeconds(2));
+			VerifyScreenshotOrSetException(ref exception, "Right_SwipeItems", retryTimeout: TimeSpan.FromSeconds(3));
 			App.Tap(CloseId);
 			App.WaitForNoElement("Issue 10563");
 
 			// Test Top SwipeItems
 			App.WaitForElement(OpenTopId);
 			App.Tap(OpenTopId);
 			App.WaitForElement("Issue 10563");
-			VerifyScreenshotOrSetException(ref exception, "Top_SwipeItems", retryTimeout: TimeSpan.FromSeconds(2));
+			VerifyScreenshotOrSetException(ref exception, "Top_SwipeItems", retryTimeout: TimeSpan.FromSeconds(3));
 			App.Tap(CloseId);
 			App.WaitForNoElement("Issue 10563");
 
 			// Test Bottom SwipeItems
 			App.WaitForElement(OpenBottomId);
 			App.Tap(OpenBottomId);
 			App.WaitForElement("Issue 10563");
-			VerifyScreenshotOrSetException(ref exception, "Bottom_SwipeItems", retryTimeout: TimeSpan.FromSeconds(2));
+			VerifyScreenshotOrSetException(ref exception, "Bottom_SwipeItems", retryTimeout: TimeSpan.FromSeconds(3));
 			App.Tap(CloseId);
 			App.WaitForNoElement("Issue 10563");
 

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue18751.cs

@@ -15,17 +15,16 @@ public Issue18751(TestDevice device) : base(device)
 
 		[Test]
 		[Category(UITestCategories.CollectionView)]
-		public async Task Issue18751Test()
+		public void Issue18751Test()
 		{
 			VerifyInternetConnectivity();
 
 			App.WaitForElement("WaitForStubControl");
 
-			// Load images.
-			await Task.Delay(1000);
-
-			// The test passes if you are able to see the image, name, and location of each monkey.
-			VerifyScreenshot();
+			// CollectionView uses virtualization which loads images synchronously once items are visible.
+			// Unlike ListView (Issue18896) which may have variable height row rendering delays,
+			// CollectionView's image loading completes quickly so retryTimeout handles any timing variance.
+			VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(2));
 		}
 	}
 }

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue18857.cs

@@ -24,10 +24,10 @@ public async Task GradientImageButtonBackground()
 
 			App.WaitForElement("TestImageButton");
 
-			await Task.Yield(); // Wait for Ripple Effect animation to complete.
+			await Task.Yield(); // Ensure UI thread completes pending work
 
-			Thread.Sleep(1000);
-			VerifyScreenshot(retryDelay: TimeSpan.FromSeconds(2));
+			// Use retryTimeout to wait for ripple animation to complete
+			VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(2));
 		}
 	}
 }

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue18896.cs

@@ -29,11 +29,10 @@ public void Issue18896Test()
 
 			App.ScrollUp(ListView);
 
-			// Load images and hide scrollbar.
-			Thread.Sleep(2000);
-
-			// The test passes if you are able to see the image, name, and location of each monkey.
-			VerifyScreenshot(retryDelay: TimeSpan.FromSeconds(2));
+			// ListView with HasUnevenRows may have variable height row rendering that requires
+			// additional time for images to load and scrollbar to disappear.
+			// Use retryTimeout to adaptively wait for the UI to stabilize.
+			VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(3));
 		}
 	}
 }

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue24856.cs

@@ -20,8 +20,8 @@ public void ImageButtonAspectFitWorks()
 			App.WaitForElement("WaitForStubControl");
 			App.Tap("UpdateAspect");
 
-			Thread.Sleep(1000);
-			VerifyScreenshot(retryDelay: TimeSpan.FromSeconds(2));
+			// Use retryTimeout to wait for aspect change to render
+			VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(2));
 		}
 	}
 }

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue25192.cs

@@ -17,8 +17,8 @@ public Issue25192(TestDevice testDevice) : base(testDevice)
 		public void CarouselViewShouldRenderCorrectly()
 		{
 			App.WaitForElement("Item1");
-			Thread.Sleep(1000); // Wait for carouselView items loading
-			VerifyScreenshot();
+			// Use retryTimeout to wait for CarouselView items to fully load and render
+			VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(2));
 		}
 	}
 }

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue27418.cs

@@ -15,10 +15,8 @@ public Issue27418(TestDevice device) : base(device) { }
 		public void CarouselItemsShouldRenderProperly()
 		{
 			App.WaitForElement("CarouselView");
-#if WINDOWS
-            Thread.Sleep(2000); // Wait for scrollbar to disappear to avoid flaky test failures in CI
-#endif
-			VerifyScreenshot();
+			// Use retryTimeout to wait for scrollbar to disappear on Windows
+			VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(2));
 		}
 	}
 }

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28657.cs

@@ -18,11 +18,10 @@ public void CellLayoutUpdatesCorrectlyAfterDeviceOrientationChanges()
     {
         App.WaitForElement("StubLabel");
         App.SetOrientationLandscape();
-        Thread.Sleep(400);
-        VerifyScreenshot("Issue28657_Landscape");
+        // Use retryTimeout to wait for orientation change to complete
+        VerifyScreenshot("Issue28657_Landscape", retryTimeout: TimeSpan.FromSeconds(2));
         App.SetOrientationPortrait();
-        Thread.Sleep(400);
-        VerifyScreenshot("Issue28657_Portrait");
+        VerifyScreenshot("Issue28657_Portrait", retryTimeout: TimeSpan.FromSeconds(2));
     }
 }
 #endif

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30575.cs

@@ -15,7 +15,7 @@ public Issue30575(TestDevice device) : base(device) { }
 	public void WebViewShouldNotMirrored()
 	{
 		App.WaitForElement("WebViewLabel");
-		Thread.Sleep(3000);
-		VerifyScreenshot();
+		// Use retryTimeout to wait for WebView content to fully load
+		VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(3));
 	}
 }