Added simple Arragement unit test

UnitTests/View/ArrangementTests.cs

@@ -0,0 +1,17 @@
+using System.Text;
+using Xunit.Abstractions;
+
+namespace Terminal.Gui.ViewTests;
+
+public class ArrangementTests (ITestOutputHelper output)
+{
+    private readonly ITestOutputHelper _output = output;
+
+    // Test that TopResizable and Movable are mutually exclusive and Movable wins
+    [Fact]
+    public void TopResizableAndMovableMutuallyExclusive ()
+    {
+      // TODO: Write test.
+    }
+
+}

UnitTests/Views/ToplevelTests.cs

@@ -25,6 +25,13 @@ public class ToplevelTests
         Assert.False (top.IsOverlapped);
     }
 
+    [Fact]
+    public void Arrangement_Is_Movable ()
+    {
+        var top = new Toplevel ();
+        Assert.Equal (ViewArrangement.Movable, top.Arrangement);
+    }
+
 #if BROKE_IN_2927
     // BUGBUG: The name of this test does not match what it does. 
     [Fact]