Hide test hit directly in explosion scene

osu.Game.Rulesets.Taiko.Tests/DrawableTestHit.cs

@@ -22,6 +22,12 @@ namespace osu.Game.Rulesets.Taiko.Tests
             HitObject.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());
         }
 
+        protected override void UpdateInitialTransforms()
+        {
+            // base implementation in DrawableHitObject forces alpha to 1.
+            // suppress locally to allow hiding the visuals wherever necessary.
+        }
+
         [BackgroundDependencyLoader]
         private void load()
         {

osu.Game.Rulesets.Taiko.Tests/Skinning/TestSceneHitExplosion.cs

@@ -35,7 +35,9 @@ namespace osu.Game.Rulesets.Taiko.Tests.Skinning
                 RelativeSizeAxes = Axes.Both,
                 Children = new Drawable[]
                 {
-                    hit,
+                    // the hit needs to be added to hierarchy in order for nested objects to be created correctly.
+                    // setting zero alpha is supposed to prevent the test from looking broken.
+                    hit.With(h => h.Alpha = 0),
                     new HitExplosion(hit, hit.Type)
                     {
                         Anchor = Anchor.Centre,