fix popup tests.

tests/Avalonia.Controls.UnitTests/Primitives/PopupRootTests.cs

@@ -77,8 +77,13 @@ namespace Avalonia.Controls.UnitTests.Primitives
 
                 var templatedChild = ((Visual)target.Host).GetVisualChildren().Single();
                 
-                Assert.IsType<VisualLayerManager>(templatedChild);
-                var contentPresenter = templatedChild.VisualChildren.Single();
+                Assert.IsType<Panel>(templatedChild);
+
+                var visualLayerManager = templatedChild.GetVisualChildren().Skip(1).Single();
+
+                Assert.IsType<VisualLayerManager>(visualLayerManager);
+
+                var contentPresenter = visualLayerManager.VisualChildren.Single();
                 Assert.IsType<ContentPresenter>(contentPresenter);
                 
                 

tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs

@@ -275,6 +275,8 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 Assert.Equal(
                     new[]
                     {
+                        "Panel",
+                        "Border",
                         "VisualLayerManager",
                         "ContentPresenter",
                         "ContentPresenter",
@@ -289,6 +291,8 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 Assert.Equal(
                     new object[]
                     {
+                        popupRoot,
+                        popupRoot,
                         popupRoot,
                         popupRoot,
                         target,