Added more unit tests (#20154)

Author: kubaflo

src/Controls/tests/Core.UnitTests/GridTests.cs

@@ -2394,17 +2394,6 @@ public void MinimumHeightRequestInAutoCells()
 			Assert.Equal(boxRow0Column1.MinimumHeightRequest, boxRow0Column1.Height);
 		}
 
-		[Fact]
-		public void ShouldPropagateVisibilityToChildren()
-		{
-			var grid = new Grid() { IsVisible = false };
-			var label = new Label() { IsVisible = true };
-			grid.Add(label);
-
-			Assert.False(label.IsVisible);
-			Assert.Equal(grid.IsVisible, label.IsVisible);
-		}
-
 		// because the constraint is internal, we need this
 		public enum HackLayoutConstraint
 		{

src/Controls/tests/Core.UnitTests/VisualElementTests.cs

@@ -237,5 +237,79 @@ public async Task ShadowDoesNotLeak()
 
 			Assert.False(reference.IsAlive, "VisualElement should not be alive!");
 		}
+
+		[Fact]
+		public void ShouldPropagateVisibilityToChildren()
+		{
+			var grid = new Grid() { IsVisible = false };
+			var label = new Label() { IsVisible = true };
+			grid.Add(label);
+
+			Assert.False(label.IsVisible);
+			Assert.Equal(grid.IsVisible, label.IsVisible);
+		}
+
+		[Theory]
+		[InlineData(false, true, true, false, false, false)]
+		[InlineData(true, false, true, true, false, false)]
+		public void IsVisiblePropagates(bool rootIsVisible, bool nestedIsVisible, bool childIsVisible, bool expectedRootVisibility, bool expectedNestedVisibility, bool expectedChildVisibility)
+		{
+			var root = new Grid() { IsVisible = rootIsVisible };
+			var nested = new Grid() { IsVisible = nestedIsVisible };
+			var child = new Button() { IsVisible = childIsVisible };
+
+			nested.Add(child);
+			root.Add(nested);
+
+			Assert.Equal(root.IsVisible, expectedRootVisibility);
+			Assert.Equal(nested.IsVisible, expectedNestedVisibility);
+			Assert.Equal(child.IsVisible, expectedChildVisibility);
+		}
+
+		[Fact]
+		public void IsVisibleParentCorrectlyUnsetsPropagatedChange()
+		{
+			var button = new Button();
+			var grid = new Grid { button };
+
+			grid.IsVisible = false;
+			Assert.False(button.IsVisible);
+
+			grid.IsVisible = true;
+			Assert.True(button.IsVisible);
+		}
+
+		[Fact]
+		public void ButtonShouldStayHiddenIfExplicitlySet()
+		{
+			var button = new Button { IsVisible = false };
+			var grid = new Grid { button };
+
+			grid.IsVisible = false;
+			Assert.False(button.IsVisible);
+
+			// button stays hidden if it was explicitly set
+			grid.IsVisible = true;
+			Assert.False(button.IsVisible);
+		}
+
+		[Fact]
+		public void ButtonShouldBeVisibleWhenExplicitlySetWhenParentIsVisible()
+		{
+			var button = new Button { IsVisible = false };
+			var grid = new Grid { button };
+
+			// everything is hidden
+			grid.IsVisible = false;
+			Assert.False(button.IsVisible);
+
+			// make buttin visible, but it should not appear
+			button.IsVisible = true;
+			Assert.False(button.IsVisible);
+
+			// button appears when parent appears
+			grid.IsVisible = true;
+			Assert.True(button.IsVisible);
+		}
 	}
 }