Merge pull request #1377 from AvaloniaUI/fixes/1376-textbox-scrollbar

Fix TextBox ScrollBar visibility.

src/Avalonia.Controls/TextBox.cs

@@ -103,7 +103,7 @@ namespace Avalonia.Controls
                     if (acceptsReturn)
                     {
                         return wrapping == TextWrapping.NoWrap ?
-                            ScrollBarVisibility.Visible :
+                            ScrollBarVisibility.Auto :
                             ScrollBarVisibility.Disabled;
                     }
                     else

tests/Avalonia.Controls.UnitTests/TextBoxTests.cs

@@ -4,10 +4,12 @@
 using System;
 using System.Reactive.Linq;
 using Avalonia.Controls.Presenters;
+using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.Markup.Xaml.Data;
+using Avalonia.Media;
 using Avalonia.Platform;
 using Avalonia.UnitTests;
 using Moq;
@@ -245,6 +247,28 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Theory]
+        [InlineData(new object[] { false, TextWrapping.NoWrap, ScrollBarVisibility.Hidden })]
+        [InlineData(new object[] { false, TextWrapping.Wrap, ScrollBarVisibility.Hidden })]
+        [InlineData(new object[] { true, TextWrapping.NoWrap, ScrollBarVisibility.Auto })]
+        [InlineData(new object[] { true, TextWrapping.Wrap, ScrollBarVisibility.Disabled })]
+        public void Has_Correct_Horizontal_ScrollBar_Visibility(
+            bool acceptsReturn,
+            TextWrapping wrapping,
+            ScrollBarVisibility expected)
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var target = new TextBox
+                {
+                    AcceptsReturn = acceptsReturn,
+                    TextWrapping = wrapping,
+                };
+
+                Assert.Equal(expected, ScrollViewer.GetHorizontalScrollBarVisibility(target));
+            }
+        }
+
         private static TestServices Services => TestServices.MockThreadingInterface.With(
             standardCursorFactory: Mock.Of<IStandardCursorFactory>());