gui-cs.Terminal.Gui/UnitTests/Views/ButtonTests.cs

using Xunit;
using Xunit.Abstractions;

namespace Terminal.Gui.ViewsTests; 

public class ButtonTests {
	readonly ITestOutputHelper _output;

	public ButtonTests (ITestOutputHelper output) => _output = output;

	[Fact] [SetupFakeDriver]
	public void Constructors_Defaults ()
	{
		var btn = new Button ();
		Assert.Equal (string.Empty, btn.Text);
		btn.BeginInit ();
		btn.EndInit ();

		Assert.Equal ($"{CM.Glyphs.LeftBracket}  {CM.Glyphs.RightBracket}", btn.TextFormatter.Text);
		Assert.False (btn.IsDefault);
		Assert.Equal (TextAlignment.Centered, btn.TextAlignment);
		Assert.Equal ('_', btn.HotKeySpecifier.Value);
		Assert.True (btn.CanFocus);
		Assert.Equal (new Rect (0, 0, 4, 1), btn.Bounds);
		Assert.Equal (new Rect (0, 0, 4, 1), btn.Frame);
		Assert.Equal ($"{CM.Glyphs.LeftBracket}  {CM.Glyphs.RightBracket}", btn.TextFormatter.Text);
		Assert.False (btn.IsDefault);
		Assert.Equal (TextAlignment.Centered, btn.TextAlignment);
		Assert.Equal ('_', btn.HotKeySpecifier.Value);
		Assert.True (btn.CanFocus);
		Assert.Equal (new Rect (0, 0, 4, 1), btn.Bounds);
		Assert.Equal (new Rect (0, 0, 4, 1), btn.Frame);

		Assert.Equal (string.Empty, btn.Title);
		Assert.Equal (KeyCode.Null, btn.HotKey);

		btn.Draw ();

		var expected = @$"
{CM.Glyphs.LeftBracket}  {CM.Glyphs.RightBracket}
";
		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);

		btn = new Button ("ARGS", true) { Text = "_Test" };
		btn.BeginInit ();
		btn.EndInit ();
		Assert.Equal ('_', btn.HotKeySpecifier.Value);
		Assert.Equal (Key.T, btn.HotKey);
		Assert.Equal ("_Test", btn.Text);

		Assert.Equal ($"{CM.Glyphs.LeftBracket}{CM.Glyphs.LeftDefaultIndicator} Test {CM.Glyphs.RightDefaultIndicator}{CM.Glyphs.RightBracket}", btn.TextFormatter.Format ());
		Assert.True (btn.IsDefault);
		Assert.Equal (TextAlignment.Centered, btn.TextAlignment);
		Assert.True (btn.CanFocus);
		Assert.Equal (new Rect (0, 0, 10, 1), btn.Bounds);
		Assert.Equal (new Rect (0, 0, 10, 1), btn.Frame);
		Assert.Equal (KeyCode.T, btn.HotKey);

		btn = new Button (1, 2, "_abc", true);
		btn.BeginInit ();
		btn.EndInit ();
		Assert.Equal ("_abc", btn.Text);
		Assert.Equal (Key.A, btn.HotKey);

		Assert.Equal ($"{CM.Glyphs.LeftBracket}{CM.Glyphs.LeftDefaultIndicator} abc {CM.Glyphs.RightDefaultIndicator}{CM.Glyphs.RightBracket}", btn.TextFormatter.Format ());
		Assert.True (btn.IsDefault);
		Assert.Equal (TextAlignment.Centered, btn.TextAlignment);
		Assert.Equal ('_', btn.HotKeySpecifier.Value);
		Assert.True (btn.CanFocus);

		Application.Driver.ClearContents ();
		btn.Draw ();

		expected = @$"
 {CM.Glyphs.LeftBracket}{CM.Glyphs.LeftDefaultIndicator} abc {CM.Glyphs.RightDefaultIndicator}{CM.Glyphs.RightBracket}
";
		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);

		Assert.Equal (new Rect (0, 0, 10, 1), btn.Bounds);
		Assert.Equal (new Rect (1, 2, 10, 1), btn.Frame);
	}

	[Fact]
	[AutoInitShutdown]
	public void KeyBindings_Command ()
	{
		var clicked = false;
		var btn = new Button ("_Test");
		btn.Clicked += (s, e) => clicked = true;
		Application.Top.Add (btn);
		Application.Begin (Application.Top);

		// Hot key. Both alone and with alt
		Assert.Equal (KeyCode.T, btn.HotKey);
		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.T)));
		Assert.True (clicked);
		clicked = false;

		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.T | KeyCode.AltMask)));
		Assert.True (clicked);
		clicked = false;

		Assert.True (btn.NewKeyDownEvent (btn.HotKey));
		Assert.True (clicked);
		clicked = false;
		Assert.True (btn.NewKeyDownEvent (btn.HotKey));
		Assert.True (clicked);
		clicked = false;

		// IsDefault = false
		// Space and Enter should work
		Assert.False (btn.IsDefault);
		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.Enter)));
		Assert.True (clicked);
		clicked = false;

		// IsDefault = true
		// Space and Enter should work
		btn.IsDefault = true;
		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.Enter)));
		Assert.True (clicked);
		clicked = false;

		// Toplevel does not handle Enter, so it should get passed on to button
		Assert.True (Application.Top.NewKeyDownEvent (new Key (KeyCode.Enter)));
		Assert.True (clicked);
		clicked = false;

		// Direct
		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.Enter)));
		Assert.True (clicked);
		clicked = false;

		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.Space)));
		Assert.True (clicked);
		clicked = false;

		Assert.True (btn.NewKeyDownEvent (new Key ((KeyCode)'T')));
		Assert.True (clicked);
		clicked = false;

		// Change hotkey:
		btn.Text = "Te_st";
		Assert.True (btn.NewKeyDownEvent (btn.HotKey));
		Assert.True (clicked);
		clicked = false;
	}

	[Fact]
	[AutoInitShutdown]
	public void HotKeyChange_Works ()
	{
		var clicked = false;
		var btn = new Button ("_Test");
		btn.Clicked += (s, e) => clicked = true;
		Application.Top.Add (btn);
		Application.Begin (Application.Top);

		Assert.Equal (KeyCode.T, btn.HotKey);
		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.T)));
		Assert.True (clicked);

		clicked = false;
		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.T | KeyCode.AltMask)));
		Assert.True (clicked);

		clicked = false;
		btn.HotKey = KeyCode.E;
		Assert.True (btn.NewKeyDownEvent (new Key (KeyCode.E | KeyCode.AltMask)));
		Assert.True (clicked);
	}

	/// <summary>
	/// This test demonstrates how to change the activation key for Button
	/// as described in the README.md keyboard handling section
	/// </summary>
	[Fact]
	[AutoInitShutdown]
	public void KeyBindingExample ()
	{
		var pressed = 0;
		var btn = new Button ("Press Me");

		btn.Clicked += (s, e) => pressed++;

		// The Button class supports the Default and Accept command
		Assert.Contains (Command.Default, btn.GetSupportedCommands ());
		Assert.Contains (Command.Accept, btn.GetSupportedCommands ());

		Application.Top.Add (btn);
		Application.Begin (Application.Top);
		Application.Top.Add (btn);
		Application.Begin (Application.Top);

		// default keybinding is Space which results in keypress
		Application.OnKeyDown (new Key ((KeyCode)' '));
		Assert.Equal (1, pressed);

		// remove the default keybinding (Space)
		btn.KeyBindings.Clear (Command.Default, Command.Accept);

		// After clearing the default keystroke the Space button no longer does anything for the Button
		Application.OnKeyDown (new Key ((KeyCode)' '));
		Assert.Equal (1, pressed);

		// Set a new binding of b for the click (Accept) event
		btn.KeyBindings.Add (KeyCode.B, Command.Default, Command.Accept);

		// now pressing B should call the button click event
		Application.OnKeyDown (new Key (KeyCode.B));
		Assert.Equal (2, pressed);

		// now pressing Shift-B should NOT call the button click event
		Application.OnKeyDown (new Key (KeyCode.ShiftMask | KeyCode.B));
		Assert.Equal (2, pressed);

		// now pressing Alt-B should NOT call the button click event
		Application.OnKeyDown (new Key (KeyCode.AltMask | KeyCode.B));
		Assert.Equal (2, pressed);

		// now pressing Shift-Alt-B should NOT call the button click event
		Application.OnKeyDown (new Key (KeyCode.ShiftMask | KeyCode.AltMask | KeyCode.B));
		Assert.Equal (2, pressed);
	}

	[Fact]
	public void TestAssignTextToButton ()
	{
		View b = new Button { Text = "heya" };
		Assert.Equal ("heya", b.Text);
		Assert.Contains ("heya", b.TextFormatter.Text);
		b.Text = "heyb";
		Assert.Equal ("heyb", b.Text);
		Assert.Contains ("heyb", b.TextFormatter.Text);

		// with cast
		Assert.Equal ("heyb", ((Button)b).Text);
	}

	[Fact]
	public void Setting_Empty_Text_Sets_HoKey_To_KeyNull ()
	{
		var super = new View ();
		var btn = new Button ("_Test");
		super.Add (btn);
		super.BeginInit ();
		super.EndInit ();

		Assert.Equal ("_Test", btn.Text);
		Assert.Equal (KeyCode.T, btn.HotKey);

		btn.Text = string.Empty;
		Assert.Equal ("", btn.Text);
		Assert.Equal (KeyCode.Null, btn.HotKey);
		btn.Text = string.Empty;
		Assert.Equal ("", btn.Text);
		Assert.Equal (KeyCode.Null, btn.HotKey);

		btn.Text = "Te_st";
		Assert.Equal ("Te_st", btn.Text);
		Assert.Equal (KeyCode.S, btn.HotKey);
	}

	[Fact, AutoInitShutdown]
	public void Update_Only_On_Or_After_Initialize ()
	{
		var btn = new Button ("Say Hello 你") {
			X = Pos.Center (),
			Y = Pos.Center ()
		};
		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		win.Add (btn);
		Application.Top.Add (win);

		Assert.False (btn.IsInitialized);
		Assert.False (btn.IsInitialized);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);
		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);

		Assert.True (btn.IsInitialized);
		Assert.Equal ("Say Hello 你", btn.Text);
		Assert.Equal ($"{CM.Glyphs.LeftBracket} {btn.Text} {CM.Glyphs.RightBracket}", btn.TextFormatter.Text);
		Assert.Equal (new Rect (0, 0, 16, 1), btn.Bounds);
		var btnTxt = $"{CM.Glyphs.LeftBracket} {btn.Text} {CM.Glyphs.RightBracket}";
		var expected = @$"
┌────────────────────────────┐
│                            │
│      {btnTxt}      │
│                            │
└────────────────────────────┘
";

		var pos = TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
		Assert.Equal (new Rect (0, 0, 30, 5), pos);
	}

	[Fact, AutoInitShutdown]
	public void Update_Parameterless_Only_On_Or_After_Initialize ()
	{
		var btn = new Button {
			X = Pos.Center (),
			Y = Pos.Center (),
			Text = "Say Hello 你"
		};
		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		win.Add (btn);
		Application.Top.Add (win);

		Assert.False (btn.IsInitialized);
		Assert.False (btn.IsInitialized);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);
		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);

		Assert.True (btn.IsInitialized);
		Assert.Equal ("Say Hello 你", btn.Text);
		Assert.Equal ($"{CM.Glyphs.LeftBracket} {btn.Text} {CM.Glyphs.RightBracket}", btn.TextFormatter.Text);
		Assert.Equal (new Rect (0, 0, 16, 1), btn.Bounds);
		var btnTxt = $"{CM.Glyphs.LeftBracket} {btn.Text} {CM.Glyphs.RightBracket}";
		var expected = @$"
┌────────────────────────────┐
│                            │
│      {btnTxt}      │
│                            │
└────────────────────────────┘
";

		var pos = TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
		Assert.Equal (new Rect (0, 0, 30, 5), pos);
	}

	[Fact, AutoInitShutdown]
	public void AutoSize_Stays_True_With_EmptyText ()
	{
		var btn = new Button {
			X = Pos.Center (),
			Y = Pos.Center (),
			AutoSize = true
		};

		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		win.Add (btn);
		Application.Top.Add (win);

		Assert.True (btn.AutoSize);
		Assert.True (btn.AutoSize);

		btn.Text = "Say Hello 你";
		btn.Text = "Say Hello 你";

		Assert.True (btn.AutoSize);
		Assert.True (btn.AutoSize);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);
		var expected = @$"
┌────────────────────────────┐
│                            │
│      {CM.Glyphs.LeftBracket} Say Hello 你 {CM.Glyphs.RightBracket}      │
│                            │
└────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
	}

	[Fact, AutoInitShutdown]
	public void AutoSize_Stays_True_Center ()
	{
		var btn = new Button {
			X = Pos.Center (),
			Y = Pos.Center (),
			Text = "Say Hello 你"
		};

		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		win.Add (btn);
		Application.Top.Add (win);

		Assert.True (btn.AutoSize);
		Assert.True (btn.AutoSize);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);
		var expected = @$"
┌────────────────────────────┐
│                            │
│      {CM.Glyphs.LeftBracket} Say Hello 你 {CM.Glyphs.RightBracket}      │
│                            │
└────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);

		Assert.True (btn.AutoSize);
		btn.Text = "Say Hello 你 changed";
		Assert.True (btn.AutoSize);
		Application.Refresh ();
		expected = @$"
┌────────────────────────────┐
│                            │
│  {CM.Glyphs.LeftBracket} Say Hello 你 changed {CM.Glyphs.RightBracket}  │
│                            │
└────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
	}

	[Fact] [AutoInitShutdown]
	public void AutoSize_Stays_True_AnchorEnd ()
	{
		var btn = new Button {
			Y = Pos.Center (),
			Text = "Say Hello 你",
			AutoSize = true
		};
		var btnTxt = $"{CM.Glyphs.LeftBracket} {btn.Text} {CM.Glyphs.RightBracket}";

		btn.X = Pos.AnchorEnd () - Pos.Function (() => btn.TextFormatter.Text.GetColumns ());
		btn.X = Pos.AnchorEnd () - Pos.Function (() => btn.TextFormatter.Text.GetColumns ());

		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		win.Add (btn);
		Application.Top.Add (win);

		Assert.True (btn.AutoSize);
		Assert.True (btn.AutoSize);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);
		var expected = @$"
┌────────────────────────────┐
│                            │
│            {btnTxt}│
│                            │
└────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);

		Assert.True (btn.AutoSize);
		btn.Text = "Say Hello 你 changed";
		btnTxt = $"{CM.Glyphs.LeftBracket} {btn.Text} {CM.Glyphs.RightBracket}";
		Assert.True (btn.AutoSize);
		Application.Refresh ();
		expected = @$"
┌────────────────────────────┐
│                            │
│    {btnTxt}│
│                            │
└────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
	}

	[Fact] [AutoInitShutdown]
	public void AutoSize_False_With_Fixed_Width ()
	{
		var tab = new View ();

		var lblWidth = 8;

		var label = new Label ("Find:") {
			Y = 1,
			Width = lblWidth,
			TextAlignment = TextAlignment.Right,
			AutoSize = false
		};
		tab.Add (label);

		var txtToFind = new TextField ("Testing buttons.") {
			X = Pos.Right (label) + 1,
			Y = Pos.Top (label),
			Width = 20
		};
		tab.Add (txtToFind);

		var btnFindNext = new Button ("Find _Next") {
			X = Pos.Right (txtToFind) + 1,
			Y = Pos.Top (label),
			Width = 20,
			Enabled = !string.IsNullOrEmpty (txtToFind.Text),
			TextAlignment = TextAlignment.Centered,
			IsDefault = true,
			AutoSize = false
		};
		tab.Add (btnFindNext);

		var btnFindPrevious = new Button ("Find _Previous") {
			X = Pos.Right (txtToFind) + 1,
			Y = Pos.Top (btnFindNext) + 1,
			Width = 20,
			Enabled = !string.IsNullOrEmpty (txtToFind.Text),
			TextAlignment = TextAlignment.Centered,
			AutoSize = false
		};
		tab.Add (btnFindPrevious);

		var btnCancel = new Button ("Cancel") {
			X = Pos.Right (txtToFind) + 1,
			Y = Pos.Top (btnFindPrevious) + 2,
			Width = 20,
			TextAlignment = TextAlignment.Centered,
			AutoSize = false
		};
		tab.Add (btnCancel);

		var ckbMatchCase = new CheckBox ("Match c_ase") {
			X = 0,
			Y = Pos.Top (txtToFind) + 2,
			Checked = true
		};
		tab.Add (ckbMatchCase);

		var ckbMatchWholeWord = new CheckBox ("Match _whole word") {
			X = 0,
			Y = Pos.Top (ckbMatchCase) + 1,
			Checked = false
		};
		tab.Add (ckbMatchWholeWord);

		var tabView = new TabView {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		tabView.AddTab (new Tab () { DisplayText = "Find", View = tab }, true);

		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};

		tab.Width = label.Width + txtToFind.Width + btnFindNext.Width + 2;
		tab.Height = btnFindNext.Height + btnFindPrevious.Height + btnCancel.Height + 4;

		win.Add (tabView);
		Application.Top.Add (win);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (54, 11);

		Assert.Equal (new Rect (0, 0, 54, 11), win.Frame);
		Assert.Equal (new Rect (0, 0, 52, 9), tabView.Frame);
		Assert.Equal (new Rect (0, 0, 50, 7), tab.Frame);
		Assert.Equal (new Rect (0, 1, 8, 1), label.Frame);
		Assert.Equal (new Rect (9, 1, 20, 1), txtToFind.Frame);

		Assert.Equal (0, txtToFind.ScrollOffset);
		Assert.Equal (16, txtToFind.CursorPosition);

		Assert.Equal (new Rect (30, 1, 20, 1), btnFindNext.Frame);
		Assert.Equal (new Rect (30, 2, 20, 1), btnFindPrevious.Frame);
		Assert.Equal (new Rect (30, 4, 20, 1), btnCancel.Frame);
		Assert.Equal (new Rect (0, 3, 12, 1), ckbMatchCase.Frame);
		Assert.Equal (new Rect (0, 4, 18, 1), ckbMatchWholeWord.Frame);
		var btn1 = $"{CM.Glyphs.LeftBracket}{CM.Glyphs.LeftDefaultIndicator} Find Next {CM.Glyphs.RightDefaultIndicator}{CM.Glyphs.RightBracket}";
		var btn2 = $"{CM.Glyphs.LeftBracket} Find Previous {CM.Glyphs.RightBracket}";
		var btn3 = $"{CM.Glyphs.LeftBracket} Cancel {CM.Glyphs.RightBracket}";
		var expected = @$"
┌────────────────────────────────────────────────────┐
│╭────╮                                              │
││Find│                                              │
││    ╰─────────────────────────────────────────────╮│
││                                                  ││
││   Find: Testing buttons.       {btn1}   ││
││                               {btn2}  ││
││{CM.Glyphs.Checked} Match case                                      ││
││{CM.Glyphs.UnChecked} Match whole word                 {btn3}     ││
│└──────────────────────────────────────────────────┘│
└────────────────────────────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
	}

	[Fact] [AutoInitShutdown]
	public void Pos_Center_Layout_AutoSize_True ()
	{
		var button = new Button ("Process keys") {
			X = Pos.Center (),
			Y = Pos.Center (),
			IsDefault = true
		};
		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		win.Add (button);
		Application.Top.Add (win);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);
		Assert.True (button.AutoSize);
		Assert.Equal (new Rect (5, 1, 18, 1), button.Frame);
		var btn = $"{CM.Glyphs.LeftBracket}{CM.Glyphs.LeftDefaultIndicator} Process keys {CM.Glyphs.RightDefaultIndicator}{CM.Glyphs.RightBracket}";

		var expected = @$"
┌────────────────────────────┐
│                            │
│     {btn}     │
│                            │
└────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
	}

	[Fact] [AutoInitShutdown]
	public void Pos_Center_Layout_AutoSize_False ()
	{
		var button = new Button ("Process keys") {
			X = Pos.Center (),
			Y = Pos.Center (),
			Width = 20,
			IsDefault = true,
			AutoSize = false
		};
		var win = new Window {
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};
		win.Add (button);
		Application.Top.Add (win);

		Application.Begin (Application.Top);
		((FakeDriver)Application.Driver).SetBufferSize (30, 5);
		Assert.False (button.AutoSize);
		Assert.Equal (new Rect (4, 1, 20, 1), button.Frame);
		var expected = @$"
┌────────────────────────────┐
│                            │
│     {CM.Glyphs.LeftBracket}{CM.Glyphs.LeftDefaultIndicator} Process keys {CM.Glyphs.RightDefaultIndicator}{CM.Glyphs.RightBracket}     │
│                            │
└────────────────────────────┘
";

		TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
	}

	[Fact] [AutoInitShutdown]
	public void Button_HotKeyChanged_EventFires ()
	{
		var btn = new Button ("_Yar");

		object sender = null;
		KeyChangedEventArgs args = null;

		btn.HotKeyChanged += (s, e) => {
			sender = s;
			args = e;
		btn.HotKeyChanged += (s, e) => {
			sender = s;
			args = e;

		};
		};

		btn.HotKey = KeyCode.R;
		Assert.Same (btn, sender);
		Assert.Equal (KeyCode.Y, args.OldKey);
		Assert.Equal (KeyCode.R, args.NewKey);
		btn.HotKey = KeyCode.R;
		Assert.Same (btn, sender);
		Assert.Equal (KeyCode.Y, args.OldKey);
		Assert.Equal (KeyCode.R, args.NewKey);
	}

	[Fact] [AutoInitShutdown]
	public void Button_HotKeyChanged_EventFires_WithNone ()
	{
		var btn = new Button ();

		object sender = null;
		KeyChangedEventArgs args = null;

		btn.HotKeyChanged += (s, e) => {
			sender = s;
			args = e;

		};

		btn.HotKey = KeyCode.R;
		Assert.Same (btn, sender);
		Assert.Equal (KeyCode.Null, args.OldKey);
		Assert.Equal (KeyCode.R, args.NewKey);
	}
}