Fix test in line with new expectations

Author: peppy

osu.Game.Tests/Visual/Beatmaps/TestSceneBeatmapCardThumbnail.cs

@@ -42,7 +42,7 @@ public void TestThumbnailPreview()
                 };
             });
             AddStep("enable dim", () => thumbnail.Dimmed.Value = true);
-            AddUntilStep("button visible", () => playButton.IsPresent);
+            AddUntilStep("button visible", () => playButton.Alpha == 1);
 
             AddStep("click button", () =>
             {
@@ -70,15 +70,15 @@ public void TestThumbnailPreview()
 
             AddStep("disable dim", () => thumbnail.Dimmed.Value = false);
             AddWaitStep("wait some", 3);
-            AddAssert("button still visible", () => playButton.IsPresent);
+            AddAssert("button still visible", () => playButton.Alpha == 1);
 
             // The track plays in real-time, so we need to check for progress in increments to avoid timeout.
             AddUntilStep("progress > 0.25", () => thumbnail.ChildrenOfType<PlayButton>().Single().Progress.Value > 0.25);
             AddUntilStep("progress > 0.5", () => thumbnail.ChildrenOfType<PlayButton>().Single().Progress.Value > 0.5);
             AddUntilStep("progress > 0.75", () => thumbnail.ChildrenOfType<PlayButton>().Single().Progress.Value > 0.75);
 
             AddUntilStep("wait for track to end", () => !playButton.Playing.Value);
-            AddUntilStep("button hidden", () => !playButton.IsPresent);
+            AddUntilStep("button hidden", () => playButton.Alpha == 0);
         }
 
         private void iconIs(IconUsage usage) => AddUntilStep("icon is correct", () => playButton.ChildrenOfType<SpriteIcon>().Any(icon => icon.Icon.Equals(usage)));