Add comprehensive test coverage for many controls (#737)

Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>
Co-authored-by: Copilot <198982749+Copilot@users.noreply.github.com>

tests/HeadlessTest.Ursa/Controls/ButtonGroupTests/ButtonGroupTests.cs

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+using System.Collections.ObjectModel;
+using System.Windows.Input;
+using Avalonia.Controls;
+using Avalonia.Controls.Templates;
+using Avalonia.Data;
+using Avalonia.Headless.XUnit;
+using Avalonia.LogicalTree;
+using Avalonia.VisualTree;
+using CommunityToolkit.Mvvm.Input;
+using Ursa.Controls;
+
+namespace HeadlessTest.Ursa.Controls.ButtonGroupTests;
+
+public class ButtonGroupTests
+{
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Create_Button_Containers_For_Non_Button_Items()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        var items = new ObservableCollection<string> { "Item1", "Item2", "Item3" };
+        buttonGroup.ItemsSource = items;
+
+        // Act & Assert
+        var generatedButtons = buttonGroup.GetVisualDescendants().OfType<Button>().ToList();
+        Assert.Equal(3, generatedButtons.Count);
+        
+        // Verify each button has the correct content
+        for (int i = 0; i < items.Count; i++)
+        {
+            Assert.Equal(items[i], generatedButtons[i].Content);
+        }
+    }
+
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Not_Wrap_Existing_Button_Items()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        var button1 = new Button { Content = "Button1" };
+        var button2 = new Button { Content = "Button2" };
+        buttonGroup.Items.Add(button1);
+        buttonGroup.Items.Add(button2);
+
+        // Act & Assert
+        var visualButtons = buttonGroup.GetVisualDescendants().OfType<Button>().ToList();
+        Assert.Equal(2, visualButtons.Count);
+        Assert.Contains(button1, visualButtons);
+        Assert.Contains(button2, visualButtons);
+    }
+
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Apply_CommandBinding_To_Generated_Buttons()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        var commandExecuted = false;
+        var testCommand = new RelayCommand(() => commandExecuted = true);
+        var testItem = new TestItem { Command = testCommand };
+
+        buttonGroup.CommandBinding = new Binding("Command");
+        buttonGroup.Items.Add(testItem);
+
+        // Act
+        var generatedButton = buttonGroup.GetVisualDescendants().OfType<Button>().FirstOrDefault();
+        Assert.NotNull(generatedButton);
+        
+        generatedButton.Command?.Execute(null);
+
+        // Assert
+        Assert.True(commandExecuted);
+    }
+
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Apply_CommandParameterBinding_To_Generated_Buttons()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        object? receivedParameter = null;
+        var testCommand = new RelayCommand<object>(param => receivedParameter = param);
+        var testItem = new TestItem { Command = testCommand, Parameter = "TestParam" };
+
+        buttonGroup.CommandBinding = new Binding("Command");
+        buttonGroup.CommandParameterBinding = new Binding("Parameter");
+        buttonGroup.Items.Add(testItem);
+
+        // Act
+        var generatedButton = buttonGroup.GetVisualDescendants().OfType<Button>().FirstOrDefault();
+        Assert.NotNull(generatedButton);
+        
+        generatedButton.Command?.Execute(generatedButton.CommandParameter);
+
+        // Assert
+        Assert.Equal("TestParam", receivedParameter);
+    }
+
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Apply_ContentBinding_To_Generated_Buttons()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        var testItem = new TestItem { DisplayName = "Display Content" };
+        buttonGroup.ContentBinding = new Binding("DisplayName");
+        buttonGroup.Items.Add(testItem);
+
+        // Act
+        var generatedButton = buttonGroup.GetVisualDescendants().OfType<Button>().FirstOrDefault();
+
+        // Assert
+        Assert.NotNull(generatedButton);
+        Assert.Equal("Display Content", generatedButton.Content);
+    }
+
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Apply_ItemTemplate_To_Generated_Buttons()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        var template = new FuncDataTemplate<TestItem>((item, _) => 
+            new TextBlock { Text = $"Template: {item?.DisplayName}" });
+        
+        buttonGroup.ItemTemplate = template;
+        var testItem = new TestItem { DisplayName = "Test Item" };
+        buttonGroup.Items.Add(testItem);
+
+        // Act
+        var generatedButton = buttonGroup.GetVisualDescendants().OfType<Button>().FirstOrDefault();
+
+        // Assert
+        Assert.NotNull(generatedButton);
+        Assert.Equal(template, generatedButton.ContentTemplate);
+        
+        // Since templates are applied to the content, let's verify the data context is correct
+        Assert.Equal(testItem, generatedButton.DataContext);
+    }
+
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Handle_Mixed_Button_And_Non_Button_Items()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        var existingButton = new Button { Content = "Existing Button" };
+        var stringItem = "String Item";
+        
+        buttonGroup.Items.Add(existingButton);
+        buttonGroup.Items.Add(stringItem);
+
+        // Act & Assert
+        var allButtons = buttonGroup.GetVisualDescendants().OfType<Button>().ToList();
+        Assert.Equal(2, allButtons.Count);
+        
+        // One should be the existing button, one should be generated
+        Assert.Contains(existingButton, allButtons);
+        
+        var generatedButton = allButtons.First(b => b != existingButton);
+        Assert.Equal(stringItem, generatedButton.Content);
+    }
+
+    [AvaloniaFact]
+    public void ButtonGroup_Should_Update_When_ItemsSource_Changes()
+    {
+        // Arrange
+        var window = new Window();
+        var buttonGroup = new ButtonGroup();
+        window.Content = buttonGroup;
+        window.Show();
+
+        var items = new ObservableCollection<string> { "Item1", "Item2" };
+        buttonGroup.ItemsSource = items;
+
+        // Initially should have 2 buttons
+        var initialButtons = buttonGroup.GetVisualDescendants().OfType<Button>().ToList();
+        Assert.Equal(2, initialButtons.Count);
+
+        // Act - Add an item
+        items.Add("Item3");
+
+        // Assert - Should now have 3 buttons
+        var updatedButtons = buttonGroup.GetVisualDescendants().OfType<Button>().ToList();
+        Assert.Equal(3, updatedButtons.Count);
+
+        // Act - Remove an item
+        items.RemoveAt(0);
+
+        // Assert - Should now have 2 buttons
+        var finalButtons = buttonGroup.GetVisualDescendants().OfType<Button>().ToList();
+        Assert.Equal(2, finalButtons.Count);
+    }
+}
+
+// Helper class for testing
+public class TestItem
+{
+    public string? DisplayName { get; set; }
+    public ICommand? Command { get; set; }
+    public object? Parameter { get; set; }
+}