[release/11.0.1xx-preview7] De-flake DragEvents UI test assertions

src/Controls/tests/TestCases.Shared.Tests/Tests/DragAndDropUITests.cs

@@ -33,50 +33,23 @@ public void DragEvents()
 			App.WaitForElement("LabelDragElement");
 			App.DragAndDrop("LabelDragElement", "DragTarget");
 
-			App.WaitForElement("DragStartEventsLabel");
-			var textAfterDragStart = App.FindElement("DragStartEventsLabel").GetText();
-
-			if (string.IsNullOrEmpty(textAfterDragStart))
-			{
-				Assert.Fail("Text was expected: Drag start event");
-			}
-			else
-			{
-				Assert.That(textAfterDragStart, Is.EqualTo("DragStarting"));
-			}
-
-			App.WaitForElement("DragOverEventsLabel");
-			var textAfterDragOver = App.FindElement("DragOverEventsLabel").GetText();
-			if (string.IsNullOrEmpty(textAfterDragOver))
-			{
-				Assert.Fail("Text was expected: Drag over event");
-			}
-			else
-			{
-				Assert.That(textAfterDragOver, Is.EqualTo("DragOver"));
-			}
-
-			App.WaitForElement("DragCompletedEventsLabel");
-			var textAfterDragComplete = App.FindElement("DragCompletedEventsLabel").GetText();
-			if (string.IsNullOrEmpty(textAfterDragComplete))
-			{
-				Assert.Fail("Text was expected: Drag complete event");
-			}
-			else
-			{
-				Assert.That(textAfterDragComplete, Is.EqualTo("DropCompleted"));
-			}
+			AssertEventText("DragStartEventsLabel", "DragStarting");
+			AssertEventText("DragOverEventsLabel", "DragOver");
+			AssertEventText("DragCompletedEventsLabel", "DropCompleted");
+			AssertEventText("DropEventsLabel", "Drop");
+		}
 
-			App.WaitForElement("DropEventsLabel");
-			var textAfterDrop = App.FindElement("DropEventsLabel").GetText();
-			if (string.IsNullOrEmpty(textAfterDrop))
-			{
-				Assert.Fail("Text was expected: Drop event");
-			}
-			else
-			{
-				Assert.That(textAfterDrop, Is.EqualTo("Drop"));
-			}
+		void AssertEventText(string automationId, string expectedText)
+		{
+			// Wait for the label's text to become EXACTLY the expected value. A substring wait is
+			// unreliable here because each label's placeholder (e.g. "DragOverEvents: ") already
+			// contains the expected event name (e.g. "DragOver"), so a Contains-based wait would pass
+			// immediately on the placeholder. The wait already asserts the exact text, so no separate
+			// GetText re-read is needed (it would only re-open a window for transient Appium flakiness).
+			Assert.That(
+				App.WaitForTextEqualToElement(automationId, expectedText),
+				Is.True,
+				$"Timed out waiting for {automationId} to become '{expectedText}'.");
 		}
 
 		[Test]

src/TestUtils/src/UITest.Appium/HelperExtensions.cs

@@ -1081,6 +1081,40 @@ public static bool WaitForTextToBePresentInElement(this IApp app, string automat
 			}
 		}
 
+		/// <summary>
+		/// Waits until the element's text is exactly equal to <paramref name="text"/> (ordinal), rather
+		/// than merely containing it. Use this when the element's placeholder/initial text already
+		/// contains the expected value as a substring, which would make a Contains-based wait pass
+		/// prematurely on the placeholder.
+		/// </summary>
+		public static bool WaitForTextEqualToElement(this IApp app, string automationId, string text, TimeSpan? timeout = null)
+		{
+			timeout ??= DefaultTimeout;
+			TimeSpan retryFrequency = TimeSpan.FromMilliseconds(500);
+
+			DateTime start = DateTime.Now;
+
+			while (true)
+			{
+				var element = app.FindElements(automationId).FirstOrDefault();
+
+				if (element is not null && element.TryGetText(out var s) && string.Equals(s, text, StringComparison.Ordinal))
+				{
+					return true;
+				}
+
+				long elapsed = DateTime.Now.Subtract(start).Ticks;
+				if (elapsed >= timeout.Value.Ticks)
+				{
+					Debug.WriteLine($">>>>> {elapsed} ticks elapsed, timeout value is {timeout.Value.Ticks}");
+
+					return false;
+				}
+
+				Task.Delay(retryFrequency).Wait();
+			}
+		}
+
 		/// <summary>
 		/// Repeatedly executes a query until it returns a non-empty value or the specified retry count is reached.
 		/// </summary>