Terminal.Gui/UnitTests/Views/TabViewTests.cs

using System;
using System.Globalization;
using Xunit;
using Xunit.Abstractions;

namespace Terminal.Gui.ViewsTests;

public class TabViewTests {
	readonly ITestOutputHelper _output;

	public TabViewTests (ITestOutputHelper output) => this._output = output;

	TabView GetTabView () => GetTabView (out _, out _);

	TabView GetTabView (out Tab tab1, out Tab tab2, bool initFakeDriver = true)
	{
		if (initFakeDriver) {
			InitFakeDriver ();
		}

		var tv = new TabView ();
		tv.BeginInit ();
		tv.EndInit ();
		tv.ColorScheme = new ColorScheme ();
		tv.AddTab (tab1 = new Tab () { DisplayText = "Tab1", View = new TextField("hi") { Width = 2 } }, false);
		tv.AddTab (tab2 = new Tab () { DisplayText = "Tab2", View = new Label("hi2") }, false);
		return tv;
	}

	[Fact]
	public void AddTwoTabs_SecondIsSelected ()
	{
		InitFakeDriver ();

		var tv = new TabView ();
		Tab tab1;
		Tab tab2;
		tv.AddTab (tab1 = new Tab () { DisplayText = "Tab1", View = new TextField("hi") }, false);
		tv.AddTab (tab2 = new Tab () { DisplayText = "Tab1", View = new Label("hi2") }, true);

		Assert.Equal (2, tv.Tabs.Count);
		Assert.Equal (tab2, tv.SelectedTab);

		Application.Shutdown ();
	}

	[Fact]
	public void EnsureSelectedTabVisible_NullSelect ()
	{
		var tv = GetTabView ();

		tv.SelectedTab = null;

		Assert.Null (tv.SelectedTab);
		Assert.Equal (0, tv.TabScrollOffset);

		tv.EnsureSelectedTabIsVisible ();

		Assert.Null (tv.SelectedTab);
		Assert.Equal (0, tv.TabScrollOffset);

		Application.Shutdown ();
	}

	[Fact]
	public void EnsureSelectedTabVisible_MustScroll ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		// Make tab width small to force only one tab visible at once
		tv.Width = 4;

		tv.SelectedTab = tab1;
		Assert.Equal (0, tv.TabScrollOffset);
		tv.EnsureSelectedTabIsVisible ();
		Assert.Equal (0, tv.TabScrollOffset);

		// Asking to show tab2 should automatically move scroll offset accordingly
		tv.SelectedTab = tab2;
		Assert.Equal (1, tv.TabScrollOffset);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	public void SelectedTabChanged_Called ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		tv.SelectedTab = tab1;

		Tab oldTab = null;
		Tab newTab = null;
		var called = 0;

		tv.SelectedTabChanged += (s, e) => {
			oldTab = e.OldTab;
			newTab = e.NewTab;
			called++;
		};

		tv.SelectedTab = tab2;

		Assert.Equal (1, called);
		Assert.Equal (tab1, oldTab);
		Assert.Equal (tab2, newTab);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	public void RemoveTab_ChangesSelection ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		tv.SelectedTab = tab1;
		tv.RemoveTab (tab1);

		Assert.Equal (tab2, tv.SelectedTab);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	public void RemoveTab_MultipleCalls_NotAnError ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		tv.SelectedTab = tab1;

		// Repeated calls to remove a tab that is not part of
		// the collection should be ignored
		tv.RemoveTab (tab1);
		tv.RemoveTab (tab1);
		tv.RemoveTab (tab1);
		tv.RemoveTab (tab1);

		Assert.Equal (tab2, tv.SelectedTab);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	public void RemoveAllTabs_ClearsSelection ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		tv.SelectedTab = tab1;
		tv.RemoveTab (tab1);
		tv.RemoveTab (tab2);

		Assert.Null (tv.SelectedTab);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	public void SwitchTabBy_NormalUsage ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		Tab tab3;
		Tab tab4;
		Tab tab5;

		tv.AddTab (tab3 = new Tab (), false);
		tv.AddTab (tab4 = new Tab (), false);
		tv.AddTab (tab5 = new Tab (), false);

		tv.SelectedTab = tab1;

		var called = 0;
		tv.SelectedTabChanged += (s, e) => { called++; };

		tv.SwitchTabBy (1);

		Assert.Equal (1, called);
		Assert.Equal (tab2, tv.SelectedTab);

		//reset called counter
		called = 0;

		// go right 2
		tv.SwitchTabBy (2);

		// even though we go right 2 indexes the event should only be called once
		Assert.Equal (1, called);
		Assert.Equal (tab4, tv.SelectedTab);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	public void AddTab_SameTabMoreThanOnce ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		Assert.Equal (2, tv.Tabs.Count);

		// Tab is already part of the control so shouldn't result in duplication
		tv.AddTab (tab1, false);
		tv.AddTab (tab1, false);
		tv.AddTab (tab1, false);
		tv.AddTab (tab1, false);

		Assert.Equal (2, tv.Tabs.Count);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	public void SwitchTabBy_OutOfTabsRange ()
	{
		var tv = GetTabView (out var tab1, out var tab2);

		tv.SelectedTab = tab1;
		tv.SwitchTabBy (500);

		Assert.Equal (tab2, tv.SelectedTab);

		tv.SwitchTabBy (-500);

		Assert.Equal (tab1, tv.SelectedTab);

		// Shutdown must be called to safely clean up Application if Init has been called
		Application.Shutdown ();
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_False_TestThinTabView_WithLongNames ()
	{
		var tv = GetTabView (out var tab1, out var tab2, false);
		tv.Width = 10;
		tv.Height = 5;

		// Ensures that the tab bar subview gets the bounds of the parent TabView
		tv.LayoutSubviews ();

			// Test two tab names that fit 
			tab1.DisplayText = "12";
			tab2.DisplayText = "13";

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭──┬──╮   
│12│13│   
│  ╰──┴──╮
│hi      │
└────────┘", _output);

		tv.SelectedTab = tab2;

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭──┬──╮   
│12│13│   
├──╯  ╰──╮
│hi2     │
└────────┘", _output);

			tv.SelectedTab = tab1;
			// Test first tab name too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "13";

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭───────╮ 
│1234567│ 
│       ╰►
│hi      │
└────────┘", _output);

		//switch to tab2
		tv.SelectedTab = tab2;
		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭──╮      
│13│      
◄  ╰─────╮
│hi2     │
└────────┘", _output);

			// now make both tabs too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "abcdefghijklmnopq";

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭───────╮ 
│abcdefg│ 
◄       ╰╮
│hi2     │
└────────┘", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_False_TabsOnBottom_False_TestThinTabView_WithLongNames ()
	{
		var tv = GetTabView (out var tab1, out var tab2, false);
		tv.Width = 10;
		tv.Height = 5;
		tv.Style = new TabStyle { ShowTopLine = false };
		tv.ApplyStyleChanges ();

		// Ensures that the tab bar subview gets the bounds of the parent TabView
		tv.LayoutSubviews ();

			// Test two tab names that fit 
			tab1.DisplayText = "12";
			tab2.DisplayText = "13";

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
│12│13│   
│  ╰──┴──╮
│hi      │
│        │
└────────┘", _output);

		tv.SelectedTab = tab2;

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
│12│13│   
├──╯  ╰──╮
│hi2     │
│        │
└────────┘", _output);

		tv.SelectedTab = tab1;

			// Test first tab name too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "13";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
│1234567│ 
│       ╰►
│hi      │
│        │
└────────┘", _output);

		//switch to tab2
		tv.SelectedTab = tab2;
		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
│13│      
◄  ╰─────╮
│hi2     │
│        │
└────────┘", _output);

			// now make both tabs too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "abcdefghijklmnopq";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
│abcdefg│ 
◄       ╰╮
│hi2     │
│        │
└────────┘", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_False_TestTabView_Width4 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 4;
		tv.Height = 5;
		tv.LayoutSubviews ();

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭─╮ 
│T│ 
│ ╰►
│hi│
└──┘", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_False_TabsOnBottom_False_TestTabView_Width4 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 4;
		tv.Height = 5;
		tv.Style = new TabStyle { ShowTopLine = false };
		tv.ApplyStyleChanges ();
		tv.LayoutSubviews ();

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
│T│ 
│ ╰►
│hi│
│  │
└──┘", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_False_TestTabView_Width3 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 3;
		tv.Height = 5;
		tv.LayoutSubviews ();

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭╮ 
││ 
│╰►
│h│
└─┘", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_False_TabsOnBottom_False_TestTabView_Width3 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 3;
		tv.Height = 5;
		tv.Style = new TabStyle { ShowTopLine = false };
		tv.ApplyStyleChanges ();
		tv.LayoutSubviews ();

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
││ 
│╰►
│h│
│ │
└─┘", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_True_TestThinTabView_WithLongNames ()
	{
		var tv = GetTabView (out var tab1, out var tab2, false);
		tv.Width = 10;
		tv.Height = 5;
		tv.Style = new TabStyle { TabsOnBottom = true };
		tv.ApplyStyleChanges ();

		// Ensures that the tab bar subview gets the bounds of the parent TabView
		tv.LayoutSubviews ();

			// Test two tab names that fit 
			tab1.DisplayText = "12";
			tab2.DisplayText = "13";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi      │
│  ╭──┬──╯
│12│13│   
╰──┴──╯   ", _output);

			// Test first tab name too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "13";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi      │
│       ╭►
│1234567│ 
╰───────╯ ", _output);

		//switch to tab2
		tv.SelectedTab = tab2;
		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi2     │
◄  ╭─────╯
│13│      
╰──╯      ", _output);

			// now make both tabs too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "abcdefghijklmnopq";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi2     │
◄       ╭╯
│abcdefg│ 
╰───────╯ ", _output);
		}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_False_TabsOnBottom_True_TestThinTabView_WithLongNames ()
	{
		var tv = GetTabView (out var tab1, out var tab2, false);
		tv.Width = 10;
		tv.Height = 5;
		tv.Style = new TabStyle { ShowTopLine = false, TabsOnBottom = true };
		tv.ApplyStyleChanges ();

		// Ensures that the tab bar subview gets the bounds of the parent TabView
		tv.LayoutSubviews ();

			// Test two tab names that fit 
			tab1.DisplayText = "12";
			tab2.DisplayText = "13";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi      │
│        │
│  ╭──┬──╯
│12│13│   ", _output);

		tv.SelectedTab = tab2;

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi2     │
│        │
├──╮  ╭──╯
│12│13│   ", _output);

		tv.SelectedTab = tab1;

			// Test first tab name too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "13";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi      │
│        │
│       ╭►
│1234567│ ", _output);

		//switch to tab2
		tv.SelectedTab = tab2;
		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi2     │
│        │
◄  ╭─────╯
│13│      ", _output);

			// now make both tabs too long
			tab1.DisplayText = "12345678910";
			tab2.DisplayText = "abcdefghijklmnopq";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌────────┐
│hi2     │
│        │
◄       ╭╯
│abcdefg│ ", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_True_TestTabView_Width4 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 4;
		tv.Height = 5;
		tv.Style = new TabStyle { TabsOnBottom = true };
		tv.ApplyStyleChanges ();
		tv.LayoutSubviews ();

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌──┐
│hi│
│ ╭►
│T│ 
╰─╯ ", _output);
		}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_False_TabsOnBottom_True_TestTabView_Width4 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 4;
		tv.Height = 5;
		tv.Style = new TabStyle { ShowTopLine = false, TabsOnBottom = true };
		tv.ApplyStyleChanges ();
		tv.LayoutSubviews ();

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌──┐
│hi│
│  │
│ ╭►
│T│ ", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_True_TestTabView_Width3 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 3;
		tv.Height = 5;
		tv.Style = new TabStyle { TabsOnBottom = true };
		tv.ApplyStyleChanges ();
		tv.LayoutSubviews ();

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌─┐
│h│
│╭►
││ 
╰╯ ", _output);
		}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_False_TabsOnBottom_True_TestTabView_Width3 ()
	{
		var tv = GetTabView (out _, out _, false);
		tv.Width = 3;
		tv.Height = 5;
		tv.Style = new TabStyle { ShowTopLine = false, TabsOnBottom = true };
		tv.ApplyStyleChanges ();
		tv.LayoutSubviews ();

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌─┐
│h│
│ │
│╭►
││ ", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_False_With_Unicode ()
	{
		var tv = GetTabView (out var tab1, out var tab2, false);
		tv.Width = 20;
		tv.Height = 5;

		tv.LayoutSubviews ();

			tab1.DisplayText = "Tab0";
			tab2.DisplayText = "Les Mise" + Char.ConvertFromUtf32 (Int32.Parse ("0301", NumberStyles.HexNumber)) + "rables";

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭────╮              
│Tab0│              
│    ╰─────────────►
│hi                │
└──────────────────┘", _output);

		tv.SelectedTab = tab2;

		tv.Draw ();

			TestHelpers.AssertDriverContentsWithFrameAre (@"
╭──────────────╮    
│Les Misérables│    
◄              ╰───╮
│hi2               │
└──────────────────┘", _output);
	}

	[Fact]
	[AutoInitShutdown]
	public void ShowTopLine_True_TabsOnBottom_True_With_Unicode ()
	{
		var tv = GetTabView (out var tab1, out var tab2, false);
		tv.Width = 20;
		tv.Height = 5;
		tv.Style = new TabStyle { TabsOnBottom = true };
		tv.ApplyStyleChanges ();

		tv.LayoutSubviews ();

			tab1.DisplayText = "Tab0";
			tab2.DisplayText = "Les Mise" + Char.ConvertFromUtf32 (Int32.Parse ("0301", NumberStyles.HexNumber)) + "rables";

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌──────────────────┐
│hi                │
│    ╭─────────────►
│Tab0│              
╰────╯              ", _output);

		tv.SelectedTab = tab2;

		tv.Draw ();

		TestHelpers.AssertDriverContentsWithFrameAre (@"
┌──────────────────┐
│hi2               │
◄              ╭───╯
│Les Misérables│    
╰──────────────╯    ", _output);
		}

	[Fact]
	[AutoInitShutdown]
	public void MouseClick_ChangesTab ()
	{
		var tv = GetTabView (out var tab1, out var tab2, false);

		tv.Width = 20;
		tv.Height = 5;

		tv.LayoutSubviews ();

		tv.Draw ();

			var tabRow = tv.Subviews [0];
			Assert.Equal ("TabRowView", tabRow.GetType ().Name);

			TestHelpers.AssertDriverContentsAre (@"
╭────┬────╮
│Tab1│Tab2│
│    ╰────┴────────╮
│hi                │
└──────────────────┘
", _output);

			Tab clicked = null;

			tv.TabClicked += (s, e) => {
				clicked = e.Tab;
			};

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

			MouseEventEventArgs args;

			// Waving mouse around does not trigger click
			for (int i = 0; i < 100; i++) {
				args = new MouseEventEventArgs (new MouseEvent {
					X = i,
					Y = 1,
					Flags = MouseFlags.ReportMousePosition
				});
				Application.OnMouseEvent (args);
				Application.Refresh ();
				Assert.Null (clicked);
				Assert.Equal (tab1, tv.SelectedTab);
			}

			args = new MouseEventEventArgs (new MouseEvent {
				X = 3,
				Y = 1,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			Assert.Equal (tab1, clicked);
			Assert.Equal (tab1, tv.SelectedTab);

			// Click to tab2
			args = new MouseEventEventArgs (new MouseEvent {
				X = 6,
				Y = 1,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			Assert.Equal (tab2, clicked);
			Assert.Equal (tab2, tv.SelectedTab);

			// cancel navigation
			tv.TabClicked += (s, e) => {
				clicked = e.Tab;
				e.MouseEvent.Handled = true;
			};

			args = new MouseEventEventArgs (new MouseEvent {
				X = 3,
				Y = 1,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			// Tab 1 was clicked but event handler blocked navigation
			Assert.Equal (tab1, clicked);
			Assert.Equal (tab2, tv.SelectedTab);

			args = new MouseEventEventArgs (new MouseEvent {
				X = 12,
				Y = 1,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			// Clicking beyond last tab should raise event with null Tab
			Assert.Null (clicked);
			Assert.Equal (tab2, tv.SelectedTab);
		}

		[Fact, AutoInitShutdown]
		public void MouseClick_Right_Left_Arrows_ChangesTab ()
		{
			var tv = GetTabView (out var tab1, out var tab2, false);

			tv.Width = 7;
			tv.Height = 5;

			tv.LayoutSubviews ();

			tv.Draw ();

			var tabRow = tv.Subviews [0];
			Assert.Equal ("TabRowView", tabRow.GetType ().Name);

			TestHelpers.AssertDriverContentsAre (@"
╭────╮
│Tab1│
│    ╰►
│hi   │
└─────┘
", _output);

			Tab clicked = null;

			tv.TabClicked += (s, e) => {
				clicked = e.Tab;
			};

			Tab oldChanged = null;
			Tab newChanged = null;

			tv.SelectedTabChanged += (s, e) => {
				oldChanged = e.OldTab;
				newChanged = e.NewTab;
			};

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

			// Click the right arrow
			var args = new MouseEventEventArgs (new MouseEvent {
				X = 6,
				Y = 2,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			Assert.Null (clicked);
			Assert.Equal (tab1, oldChanged);
			Assert.Equal (tab2, newChanged);
			Assert.Equal (tab2, tv.SelectedTab);
			TestHelpers.AssertDriverContentsAre (@"
╭────╮
│Tab2│
◄    ╰╮
│hi2  │
└─────┘
", _output);

			// Click the left arrow
			args = new MouseEventEventArgs (new MouseEvent {
				X = 0,
				Y = 2,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			Assert.Null (clicked);
			Assert.Equal (tab2, oldChanged);
			Assert.Equal (tab1, newChanged);
			Assert.Equal (tab1, tv.SelectedTab);
			TestHelpers.AssertDriverContentsAre (@"
╭────╮
│Tab1│
│    ╰►
│hi   │
└─────┘
", _output);
		}

		[Fact, AutoInitShutdown]
		public void MouseClick_Right_Left_Arrows_ChangesTab_With_Border ()
		{
			var tv = GetTabView (out var tab1, out var tab2, false);

			tv.Width = 9;
			tv.Height = 7;

			Assert.Equal (LineStyle.None, tv.BorderStyle);
			tv.BorderStyle = LineStyle.Single;

			tv.LayoutSubviews ();

			tv.Draw ();

			var tabRow = tv.Subviews [0];
			Assert.Equal ("TabRowView", tabRow.GetType ().Name);

			TestHelpers.AssertDriverContentsAre (@"
┌───────┐
│╭────╮ │
││Tab1│ │
││    ╰►│
││hi   ││
│└─────┘│
└───────┘
", _output);

			Tab clicked = null;

			tv.TabClicked += (s, e) => {
				clicked = e.Tab;
			};

			Tab oldChanged = null;
			Tab newChanged = null;

			tv.SelectedTabChanged += (s, e) => {
				oldChanged = e.OldTab;
				newChanged = e.NewTab;
			};

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

			// Click the right arrow
			var args = new MouseEventEventArgs (new MouseEvent {
				X = 7,
				Y = 3,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			Assert.Null (clicked);
			Assert.Equal (tab1, oldChanged);
			Assert.Equal (tab2, newChanged);
			Assert.Equal (tab2, tv.SelectedTab);
			TestHelpers.AssertDriverContentsAre (@"
┌───────┐
│╭────╮ │
││Tab2│ │
│◄    ╰╮│
││hi2  ││
│└─────┘│
└───────┘
", _output);

			// Click the left arrow
			args = new MouseEventEventArgs (new MouseEvent {
				X = 1,
				Y = 3,
				Flags = MouseFlags.Button1Clicked
			});
			Application.OnMouseEvent (args);
			Application.Refresh ();
			Assert.Null (clicked);
			Assert.Equal (tab2, oldChanged);
			Assert.Equal (tab1, newChanged);
			Assert.Equal (tab1, tv.SelectedTab);
			TestHelpers.AssertDriverContentsAre (@"
┌───────┐
│╭────╮ │
││Tab1│ │
││    ╰►│
││hi   ││
│└─────┘│
└───────┘
", _output);
		}

		[Fact]
		public void EnsureValidScrollOffsets_TabScrollOffset ()
		{
			var tv = GetTabView (out var tab1, out var tab2);

			// Make tab width small to force only one tab visible at once
			tv.Width = 4;

			tv.SelectedTab = tab1;
			Assert.Equal (0, tv.TabScrollOffset);

			tv.TabScrollOffset = 10;
			tv.SelectedTab = tab2;
			Assert.Equal (1, tv.TabScrollOffset);

			tv.TabScrollOffset = -1;
			tv.SelectedTab = tab1;
			Assert.Equal (0, tv.TabScrollOffset);

			// Shutdown must be called to safely clean up Application if Init has been called
			Application.Shutdown ();
		}

		[Fact, AutoInitShutdown]
		public void ProcessKey_Down_Up_Right_Left_Home_End_PageDown_PageUp ()
		{
			var tv = GetTabView (out var tab1, out var tab2, false);

			tv.Width = 7;
			tv.Height = 5;

			var btn = new Button ("Ok") { Y = Pos.Bottom (tv) + 1, Width = 7 };

			var top = Application.Top;
			top.Add (tv, btn);
			Application.Begin (top);

			// Is the selected tab view hosting focused
			Assert.Equal (tab1, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);
			Assert.Equal (tv.SelectedTab.View, top.Focused.MostFocused);

			// Press the cursor up key to focus the selected tab
			var args = new Key (Key.CursorUp);
			Application.OnKeyDown (args);
			Application.Refresh ();
			// Is the selected tab focused
			Assert.Equal (tab1, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);

			Tab oldChanged = null;
			Tab newChanged = null;

			tv.SelectedTabChanged += (s, e) => {
				oldChanged = e.OldTab;
				newChanged = e.NewTab;
			};

			// Press the cursor right key to select the next tab
			args = new Key (Key.CursorRight);
			Application.OnKeyDown (args);
			Application.Refresh ();
			Assert.Equal (tab1, oldChanged);
			Assert.Equal (tab2, newChanged);
			Assert.Equal (tab2, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);

			// Press the cursor down key to focused the selected tab view hosting
			args =new Key (Key.CursorDown);
			Application.OnKeyDown (args);
			Application.Refresh ();
			Assert.Equal (tab2, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);
			// The tab view hosting is a label which can't be focused
			// and the View container is the focused one
			Assert.Equal (tv.Subviews [1], top.Focused.MostFocused);

			// Press the cursor up key to focus the selected tab
			args = new Key (Key.CursorUp);
			Application.OnKeyDown (args);
			Application.Refresh ();
			// Is the selected tab focused
			Assert.Equal (tab2, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);

			// Press the cursor left key to select the previous tab
			args = new Key(Key.CursorLeft);
			Application.OnKeyDown (args);
			Application.Refresh ();
			Assert.Equal (tab2, oldChanged);
			Assert.Equal (tab1, newChanged);
			Assert.Equal (tab1, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);

			// Press the end key to select the last tab
			args = new Key(Key.End);
			Application.OnKeyDown (args);
			Application.Refresh ();
			Assert.Equal (tab1, oldChanged);
			Assert.Equal (tab2, newChanged);
			Assert.Equal (tab2, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);

			// Press the home key to select the first tab
			args = new Key(Key.Home);
			Application.OnKeyDown (args);
			Application.Refresh ();
			Assert.Equal (tab2, oldChanged);
			Assert.Equal (tab1, newChanged);
			Assert.Equal (tab1, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);

			// Press the page down key to select the next set of tabs
			args = new Key(Key.PageDown);
			Application.OnKeyDown (args);
			Application.Refresh ();
			Assert.Equal (tab1, oldChanged);
			Assert.Equal (tab2, newChanged);
			Assert.Equal (tab2, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);

			// Press the page up key to select the previous set of tabs
			args = new Key(Key.PageUp);
			Application.OnKeyDown (args);
			Application.Refresh ();
			Assert.Equal (tab2, oldChanged);
			Assert.Equal (tab1, newChanged);
			Assert.Equal (tab1, tv.SelectedTab);
			Assert.Equal (tv, top.Focused);
			Assert.Equal (tv.MostFocused, top.Focused.MostFocused);
		}

	void InitFakeDriver ()
	{
		var driver = new FakeDriver ();
		Application.Init (driver);
		driver.Init ();
	}
}