Fix Border/Decorator measure with no child.

Should return border thickness + padding.

Perspex.Controls/Border.cs

@@ -87,8 +87,10 @@ namespace Perspex.Controls
                 content.Measure(availableSize.Deflate(padding));
                 return content.DesiredSize.Inflate(padding);
             }
-
-            return new Size();
+            else
+            {
+                return new Size(padding.Left + padding.Right, padding.Bottom + padding.Top);
+            }
         }
     }
 }

Perspex.Controls/Decorator.cs

@@ -82,8 +82,10 @@ namespace Perspex.Controls
                 content.Measure(availableSize.Deflate(padding));
                 return content.DesiredSize.Inflate(padding);
             }
-
-            return new Size();
+            else
+            {
+                return new Size(padding.Left + padding.Right, padding.Bottom + padding.Top);
+            }
         }
     }
 }

Tests/Perspex.Controls.UnitTests/BorderTests.cs

@@ -0,0 +1,127 @@
+// -----------------------------------------------------------------------
+// <copyright file="BorderTests.cs" company="Steven Kirk">
+// Copyright 2015 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Controls.UnitTests
+{
+    using System.Collections.Specialized;
+    using System.Linq;
+    using Xunit;
+
+    public class BorderTests
+    {
+        [Fact]
+        public void Setting_Content_Should_Set_Child_Controls_Parent()
+        {
+            var target = new Border();
+            var child = new Control();
+
+            target.Content = child;
+
+            Assert.Equal(child.Parent, target);
+            Assert.Equal(((ILogical)child).LogicalParent, target);
+        }
+
+        [Fact]
+        public void Clearing_Content_Should_Clear_Child_Controls_Parent()
+        {
+            var target = new Border();
+            var child = new Control();
+
+            target.Content = child;
+            target.Content = null;
+
+            Assert.Null(child.Parent);
+            Assert.Null(((ILogical)child).LogicalParent);
+        }
+
+        [Fact]
+        public void Content_Control_Should_Appear_In_LogicalChildren()
+        {
+            var target = new Border();
+            var child = new Control();
+
+            target.Content = child;
+
+            Assert.Equal(new[] { child }, ((ILogical)target).LogicalChildren.ToList());
+        }
+
+        [Fact]
+        public void Clearing_Content_Should_Remove_From_LogicalChildren()
+        {
+            var target = new Border();
+            var child = new Control();
+
+            target.Content = child;
+            target.Content = null;
+
+            Assert.Equal(new ILogical[0], ((ILogical)target).LogicalChildren.ToList());
+        }
+
+        [Fact]
+        public void Setting_Content_Should_Fire_LogicalChildren_CollectionChanged()
+        {
+            var target = new Border();
+            var child = new Control();
+            var called = false;
+
+            ((ILogical)target).LogicalChildren.CollectionChanged += (s, e) => 
+                called = e.Action == NotifyCollectionChangedAction.Add;
+
+            target.Content = child;
+
+            Assert.True(called);
+        }
+
+        [Fact]
+        public void Clearing_Content_Should_Fire_LogicalChildren_CollectionChanged()
+        {
+            var target = new Border();
+            var child = new Control();
+            var called = false;
+
+            target.Content = child;
+
+            ((ILogical)target).LogicalChildren.CollectionChanged += (s, e) =>
+                called = e.Action == NotifyCollectionChangedAction.Remove;
+
+            target.Content = null;
+
+            Assert.True(called);
+        }
+
+        [Fact]
+        public void Changing_Content_Should_Fire_LogicalChildren_CollectionChanged()
+        {
+            var target = new Border();
+            var child1 = new Control();
+            var child2 = new Control();
+            var called = false;
+
+            target.Content = child1;
+
+            ((ILogical)target).LogicalChildren.CollectionChanged += (s, e) =>
+                called = e.Action == NotifyCollectionChangedAction.Replace;
+
+            target.Content = child2;
+
+            Assert.True(called);
+        }
+
+        [Fact]
+        public void Measure_Should_Return_BorderThickness_Plus_Padding_When_No_Child_Present()
+        {
+            var target = new Border
+            {
+                Padding = new Thickness(6),
+                BorderThickness = 4,
+            };
+
+            target.Measure(new Size(100, 100));
+
+            Assert.Equal(new Size(20, 20), target.DesiredSize);
+        }
+    }
+}

Tests/Perspex.Controls.UnitTests/DecoratorTests.cs

@@ -109,5 +109,18 @@ namespace Perspex.Controls.UnitTests
 
             Assert.True(called);
         }
+
+        [Fact]
+        public void Measure_Should_Return_Padding_When_No_Child_Present()
+        {
+            var target = new Decorator
+            {
+                Padding = new Thickness(8),
+            };
+
+            target.Measure(new Size(100, 100));
+
+            Assert.Equal(new Size(16, 16), target.DesiredSize);
+        }
     }
 }

Tests/Perspex.Controls.UnitTests/Perspex.Controls.UnitTests.csproj

@@ -89,6 +89,7 @@
   </Choose>
   <ItemGroup>
     <Compile Include="ContentPresenterTests.cs" />
+    <Compile Include="BorderTests.cs" />
     <Compile Include="DropDownTests.cs" />
     <Compile Include="Presenters\ItemsPresenterTests.cs" />
     <Compile Include="ScrollContentPresenterTests.cs" />