Add CheckBox tests.

.editorconfig

@@ -137,7 +137,7 @@ space_within_single_line_array_initializer_braces = true
 csharp_wrap_before_ternary_opsigns = false
 
 # Xaml files
-[*.xaml]
+[*.{xaml,axaml}]
 indent_size = 2
 
 # Xml project files

Avalonia.sln

@@ -234,7 +234,7 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MiniMvvm", "samples\MiniMvv
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "IntegrationTestApp", "samples\IntegrationTestApp\IntegrationTestApp.csproj", "{676D6BFD-029D-4E43-BFC7-3892265CE251}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Avalonia.IntegrationTests.Win32", "tests\Avalonia.IntegrationTests.Win32\Avalonia.IntegrationTests.Win32.csproj", "{F2CE566B-E7F6-447A-AB1A-3F574A6FE43A}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Avalonia.IntegrationTests.Win32", "tests\Avalonia.IntegrationTests.Win32\Avalonia.IntegrationTests.Win32.csproj", "{F2CE566B-E7F6-447A-AB1A-3F574A6FE43A}"
 EndProject
 Global
 	GlobalSection(SharedMSBuildProjectFiles) = preSolution
@@ -2235,6 +2235,7 @@ Global
 		{29132311-1848-4FD6-AE0C-4FF841151BD3} = {9B9E3891-2366-4253-A952-D08BCEB71098}
 		{7D2D3083-71DD-4CC9-8907-39A0D86FB322} = {3743B0F2-CC41-4F14-A8C8-267F579BF91E}
 		{39D7B147-1A5B-47C2-9D01-21FB7C47C4B3} = {9B9E3891-2366-4253-A952-D08BCEB71098}
+		{86C53C40-57AA-45B8-AD42-FAE0EFDF0F2B} = {A689DEF5-D50F-4975-8B72-124C9EB54066}
 		{854568D5-13D1-4B4F-B50D-534DC7EFD3C9} = {86C53C40-57AA-45B8-AD42-FAE0EFDF0F2B}
 		{638580B0-7910-40EF-B674-DCB34DA308CD} = {A0CC0258-D18C-4AB3-854F-7101680FC3F9}
 		{CBC4FF2F-92D4-420B-BE21-9FE0B930B04E} = {B39A8919-9F95-48FE-AD7B-76E08B509888}

samples/IntegrationTestApp/MainWindow.axaml

@@ -19,6 +19,15 @@
         </Button>
       </StackPanel>
     </TabItem>
+
+    <TabItem Header="CheckBox">
+      <StackPanel>
+        <CheckBox AutomationProperties.AutomationId="UncheckedCheckBox">Unchecked</CheckBox>
+        <CheckBox AutomationProperties.AutomationId="CheckedCheckBox" IsChecked="True">Checked</CheckBox>
+        <CheckBox AutomationProperties.AutomationId="ThreeStateCheckBox" IsThreeState="True" IsChecked="{x:Null}">ThreeState</CheckBox>
+      </StackPanel>
+    </TabItem>
+      
     <TabItem Header="ComboBox">
       <StackPanel>
         <ComboBox AutomationProperties.AutomationId="UnselectedComboBox">

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

@@ -35,5 +35,8 @@ namespace Avalonia.Automation.Peers
         {
             return AutomationControlType.Button;
         }
+
+        protected override bool IsContentElementCore() => true;
+        protected override bool IsControlElementCore() => true;
     }
 }

tests/Avalonia.IntegrationTests.Win32/CheckBoxTests.cs

@@ -0,0 +1,72 @@
+using OpenQA.Selenium.Appium.Windows;
+using Xunit;
+
+namespace Avalonia.IntegrationTests.Win32
+{
+    [Collection("Default")]
+    public class CheckBoxTests
+    {
+        private WindowsDriver<WindowsElement> _session;
+
+        public CheckBoxTests(TestAppFixture fixture)
+        {
+            _session = fixture.Session;
+
+            var tabs = _session.FindElementByAccessibilityId("MainTabs");
+            var tab = tabs.FindElementByName("CheckBox");
+            tab.Click();
+        }
+
+        [Fact]
+        public void UncheckedCheckBox()
+        {
+            var checkBox = _session.FindElementByAccessibilityId("UncheckedCheckBox");
+
+            Assert.Equal("Unchecked", checkBox.Text);
+            Assert.False(checkBox.Selected);
+            Assert.Equal("0", checkBox.GetAttribute("Toggle.ToggleState"));
+
+            checkBox.Click();
+
+            Assert.True(checkBox.Selected);
+            Assert.Equal("1", checkBox.GetAttribute("Toggle.ToggleState"));
+        }
+
+        [Fact]
+        public void CheckedCheckBox()
+        {
+            var checkBox = _session.FindElementByAccessibilityId("CheckedCheckBox");
+
+            Assert.Equal("Checked", checkBox.Text);
+            Assert.True(checkBox.Selected);
+            Assert.Equal("1", checkBox.GetAttribute("Toggle.ToggleState"));
+
+            checkBox.Click();
+
+            Assert.False(checkBox.Selected);
+            Assert.Equal("0", checkBox.GetAttribute("Toggle.ToggleState"));
+        }
+
+        [Fact]
+        public void ThreeStateCheckBox()
+        {
+            var checkBox = _session.FindElementByAccessibilityId("ThreeStateCheckBox");
+
+            Assert.Equal("ThreeState", checkBox.Text);
+            Assert.Equal("2", checkBox.GetAttribute("Toggle.ToggleState"));
+
+            checkBox.Click();
+
+            Assert.False(checkBox.Selected);
+            Assert.Equal("0", checkBox.GetAttribute("Toggle.ToggleState"));
+
+            checkBox.Click();
+
+            Assert.True(checkBox.Selected);
+            Assert.Equal("1", checkBox.GetAttribute("Toggle.ToggleState"));
+
+            checkBox.Click();
+            Assert.Equal("2", checkBox.GetAttribute("Toggle.ToggleState"));
+        }
+    }
+}

tests/Avalonia.IntegrationTests.Win32/TestAppFixture.cs

@@ -1,5 +1,7 @@
 using System;
+using System.Globalization;
 using System.IO;
+using System.Runtime.InteropServices;
 using OpenQA.Selenium.Appium;
 using OpenQA.Selenium.Appium.Windows;
 
@@ -19,10 +21,19 @@ namespace Avalonia.IntegrationTests.Win32
             Session = new WindowsDriver<WindowsElement>(
                 new Uri(WindowsApplicationDriverUrl),
                 opts);
+
+            // https://github.com/microsoft/WinAppDriver/issues/1025
+            SetForegroundWindow(new IntPtr(int.Parse(
+                Session.WindowHandles[0].Substring(2),
+                NumberStyles.AllowHexSpecifier)));
         }
 
         public WindowsDriver<WindowsElement> Session { get; }
 
         public void Dispose() => Session.Close();
+
+        [DllImport("user32.dll")]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        private static extern bool SetForegroundWindow(IntPtr hWnd);
     }
 }