Add ScrollBarAutomationPeer

samples/IntegrationTestApp/MainWindow.axaml

@@ -167,6 +167,9 @@
       <TabItem Header="SliderTab">
           <Slider VerticalAlignment="Top" Name="Slider" Value="30"/>
       </TabItem>
+      <TabItem Header="ScrollBarTab">
+        <ScrollBar Name="MyScrollBar" Orientation="Horizontal" AllowAutoHide="False" Width="200" Height="30" Value="20"/>
+      </TabItem>
     </TabControl>
   </DockPanel>
 </Window>

src/Avalonia.Controls/Automation/Peers/ScrollBarAutomationPeer.cs

@@ -0,0 +1,29 @@
+using Avalonia.Controls.Primitives;
+
+namespace Avalonia.Automation.Peers
+{
+    public class ScrollBarAutomationPeer : RangeBaseAutomationPeer
+    {
+        public ScrollBarAutomationPeer(ScrollBar owner) : base(owner)
+        {
+        }
+
+        override protected string GetClassNameCore()
+        {
+            return "ScrollBar";
+        }
+
+        override protected AutomationControlType GetAutomationControlTypeCore()
+        {
+            return AutomationControlType.ScrollBar;
+        }
+
+        // AutomationControlType.ScrollBar must return IsContentElement false.
+        // See http://msdn.microsoft.com/en-us/library/ms743712.aspx
+        override protected bool IsContentElementCore()
+        {
+            return false;
+        }
+
+    }
+}

src/Avalonia.Controls/Primitives/ScrollBar.cs

@@ -5,6 +5,7 @@ using Avalonia.Input;
 using Avalonia.Layout;
 using Avalonia.Threading;
 using Avalonia.Controls.Metadata;
+using Avalonia.Automation.Peers;
 
 namespace Avalonia.Controls.Primitives
 {
@@ -286,6 +287,8 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
+        protected override AutomationPeer OnCreateAutomationPeer() => new ScrollBarAutomationPeer(this);
+
         private void InvokeAfterDelay(Action handler, TimeSpan delay)
         {
             if (_timer != null)

tests/Avalonia.IntegrationTests.Appium/ScrollBarTests.cs

@@ -0,0 +1,33 @@
+using OpenQA.Selenium.Appium;
+using Xunit;
+
+namespace Avalonia.IntegrationTests.Appium
+{
+    [Collection("Default")]
+    public class ScrollBarTests
+    {
+        private readonly AppiumDriver<AppiumWebElement> _session;
+
+        public ScrollBarTests(DefaultAppFixture fixture)
+        {
+            _session = fixture.Session;
+
+            var tabs = _session.FindElementByAccessibilityId("MainTabs");
+            var tab = tabs.FindElementByName("ScrollBarTab");
+            tab.Click();
+        }
+
+        [Fact]
+        public void ScrollBar_Increases_Value_By_LargeChange_When_IncreaseButton_Is_Clicked()
+        {
+            var button = _session.FindElementByAccessibilityId("MyScrollBar");
+            Assert.True(double.Parse(button.Text) == 20);
+
+            button.Click();
+
+            // Default LargeChange value is 10 so when clicking the IncreaseButton
+            // ScrollBar value should be increased by 10.
+            Assert.Equal(30, double.Parse(button.Text));
+        }
+    }
+}