Merge pull request #6044 from AvaloniaUI/fixes/failing-debug-build-tests

Fix a couple of tests that only fail in debug mode.

src/Avalonia.X11/X11Window.cs

@@ -994,15 +994,22 @@ namespace Avalonia.X11
                 side = NetWmMoveResize._NET_WM_MOVERESIZE_SIZE_BOTTOMLEFT;
             BeginMoveResize(side, e);
         }
-        
+
         public void SetTitle(string title)
         {
-            var data = Encoding.UTF8.GetBytes(title);
-            fixed (void* pdata = data)
+            if (string.IsNullOrEmpty(title))
             {
-                XChangeProperty(_x11.Display, _handle, _x11.Atoms._NET_WM_NAME, _x11.Atoms.UTF8_STRING, 8,
-                    PropertyMode.Replace, pdata, data.Length);
-                XStoreName(_x11.Display, _handle, title);
+                XDeleteProperty(_x11.Display, _handle, _x11.Atoms._NET_WM_NAME);
+            }
+            else
+            {
+                var data = Encoding.UTF8.GetBytes(title);
+                fixed (void* pdata = data)
+                {
+                    XChangeProperty(_x11.Display, _handle, _x11.Atoms._NET_WM_NAME, _x11.Atoms.UTF8_STRING, 8,
+                        PropertyMode.Replace, pdata, data.Length);
+                    XStoreName(_x11.Display, _handle, title);
+                }
             }
         }
 

tests/Avalonia.Visuals.UnitTests/Media/PenTests.cs

@@ -59,9 +59,9 @@ namespace Avalonia.Visuals.UnitTests.Media
         }
 
         [Fact]
-        public void Equality_Is_Implemented_Between_Immutable_And_Mmutable_Pens()
+        public void Equality_Is_Implemented_Between_Immutable_And_Mutable_Pens()
         {
-            var brush = new SolidColorBrush(Colors.Red);
+            var brush = new ImmutableSolidColorBrush(Colors.Red);
             var target1 = new ImmutablePen(
                 brush: brush,
                 thickness: 2,
@@ -83,7 +83,7 @@ namespace Avalonia.Visuals.UnitTests.Media
         [Fact]
         public void Equality_Is_Implemented_Between_Mutable_And_Immutable_DashStyles()
         {
-            var brush = new SolidColorBrush(Colors.Red);
+            var brush = new ImmutableSolidColorBrush(Colors.Red);
             var target1 = new ImmutablePen(
                 brush: brush,
                 thickness: 2,