Added ScrollBarViewTests.cs file with unit tests for ScrollBarView.

UnitTests/ScrollBarViewTests.cs

@@ -0,0 +1,258 @@
+using System;
+using Xunit;
+
+namespace Terminal.Gui {
+	public class ScrollBarViewTests {
+		public class HostView : View {
+			public int Top { get; set; }
+			public int Lines { get; set; }
+			public int Left { get; set; }
+			public int Cols { get; set; }
+		}
+
+		private HostView _hostView;
+		private ScrollBarView _vertical;
+		private ScrollBarView _horizontal;
+		private bool _added;
+
+		public ScrollBarViewTests ()
+		{
+			Application.Init (new FakeDriver (), new FakeMainLoop (() => FakeConsole.ReadKey (true)));
+
+			var top = Application.Top;
+
+			_hostView = new HostView () {
+				Width = Dim.Fill (),
+				Height = Dim.Fill (),
+				Top = 0,
+				Lines = 30,
+				Left = 0,
+				Cols = 100
+			};
+
+			top.Add (_hostView);
+		}
+
+		private void AddHandlers ()
+		{
+			if (!_added) {
+				_hostView.DrawContent += _hostView_DrawContent;
+				_vertical.ChangedPosition += _vertical_ChangedPosition;
+				_horizontal.ChangedPosition += _horizontal_ChangedPosition;
+			}
+			_added = true;
+		}
+
+		private void RemoveHandlers ()
+		{
+			if (_added) {
+				_hostView.DrawContent -= _hostView_DrawContent;
+				_vertical.ChangedPosition -= _vertical_ChangedPosition;
+				_horizontal.ChangedPosition -= _horizontal_ChangedPosition;
+			}
+			_added = false;
+		}
+
+		private void _hostView_DrawContent (Rect obj)
+		{
+			_vertical.Size = _hostView.Lines;
+			_vertical.Position = _hostView.Top;
+			_horizontal.Size = _hostView.Cols;
+			_horizontal.Position = _hostView.Left;
+			_vertical.ColorScheme = _horizontal.ColorScheme = _hostView.ColorScheme;
+			if (_vertical.ShowScrollIndicator) {
+				_vertical.Redraw (obj);
+			}
+			if (_horizontal.ShowScrollIndicator) {
+				_horizontal.Redraw (obj);
+			}
+		}
+
+		private void _vertical_ChangedPosition ()
+		{
+			_hostView.Top = _vertical.Position;
+			if (_hostView.Top != _vertical.Position) {
+				_vertical.Position = _hostView.Top;
+			}
+			_hostView.SetNeedsDisplay ();
+		}
+
+		private void _horizontal_ChangedPosition ()
+		{
+			_hostView.Left = _horizontal.Position;
+			if (_hostView.Left != _horizontal.Position) {
+				_horizontal.Position = _hostView.Left;
+			}
+			_hostView.SetNeedsDisplay ();
+		}
+
+		[Fact]
+		public void Hosting_A_Null_View_To_A_ScrollBarView_Throws_ArgumentNullException ()
+		{
+			Assert.Throws<ArgumentNullException> ("The host parameter can't be null.",
+				() => new ScrollBarView (null, true));
+			Assert.Throws<ArgumentNullException> ("The host parameter can't be null.",
+				() => new ScrollBarView (null, false));
+		}
+
+		[Fact]
+		public void Hosting_A_Null_SuperView_View_To_A_ScrollBarView_Throws_ArgumentNullException ()
+		{
+			Assert.Throws<ArgumentNullException> ("The host SuperView parameter can't be null.",
+				() => new ScrollBarView (new View (), true));
+			Assert.Throws<ArgumentNullException> ("The host SuperView parameter can't be null.",
+				() => new ScrollBarView (new View (), false));
+		}
+
+		[Fact]
+		public void Hosting_A_View_To_A_ScrollBarView ()
+		{
+			RemoveHandlers ();
+
+			_vertical = new ScrollBarView (_hostView, true);
+			_horizontal = new ScrollBarView (_hostView, false);
+			_vertical.OtherScrollBarView = _horizontal;
+			_horizontal.OtherScrollBarView = _vertical;
+
+			Assert.True (_vertical.IsVertical);
+			Assert.False (_horizontal.IsVertical);
+
+			Assert.Equal (_vertical.Position, _hostView.Top);
+			Assert.NotEqual (_vertical.Size, _hostView.Lines);
+			Assert.Equal (_horizontal.Position, _hostView.Left);
+			Assert.NotEqual (_horizontal.Size, _hostView.Cols);
+
+			AddHandlers ();
+			_hostView.SuperView.LayoutSubviews ();
+			_hostView.Redraw (_hostView.Bounds);
+
+			Assert.Equal (_vertical.Position, _hostView.Top);
+			Assert.Equal (_vertical.Size, _hostView.Lines);
+			Assert.Equal (_horizontal.Position, _hostView.Left);
+			Assert.Equal (_horizontal.Size, _hostView.Cols);
+		}
+
+		[Fact]
+		public void ChangedPosition_Update_The_Hosted_View ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			_vertical.Position = 2;
+			Assert.Equal (_vertical.Position, _hostView.Top);
+
+			_horizontal.Position = 5;
+			Assert.Equal (_horizontal.Position, _hostView.Left);
+		}
+
+		[Fact]
+		public void ChangedPosition_Negative_Value ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			_vertical.Position = -20;
+			Assert.Equal (0, _vertical.Position);
+			Assert.Equal (_vertical.Position, _hostView.Top);
+
+			_horizontal.Position = -50;
+			Assert.Equal (0, _horizontal.Position);
+			Assert.Equal (_horizontal.Position, _hostView.Left);
+		}
+
+		[Fact]
+		public void DrawContent_Update_The_ScrollBarView_Position ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			_hostView.Top = 3;
+			_hostView.Redraw (_hostView.Bounds);
+			Assert.Equal (_vertical.Position, _hostView.Top);
+
+			_hostView.Left = 6;
+			_hostView.Redraw (_hostView.Bounds);
+			Assert.Equal (_horizontal.Position, _hostView.Left);
+		}
+
+		[Fact]
+		public void OtherScrollBarView_Not_Null ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			Assert.Equal (_vertical.OtherScrollBarView, _horizontal);
+			Assert.Equal (_horizontal.OtherScrollBarView, _vertical);
+		}
+
+		[Fact]
+		public void ShowScrollIndicator_Check ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			Assert.True (_vertical.ShowScrollIndicator);
+			Assert.True (_horizontal.ShowScrollIndicator);
+		}
+
+		[Fact]
+		public void KeepContentAlwaysInViewport_True ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			_vertical.Position = 50;
+			Assert.Equal (_vertical.Position, _vertical.Size - _vertical.Bounds.Height + 1);
+			Assert.Equal (_vertical.Position, _hostView.Top);
+
+			_horizontal.Position = 150;
+			Assert.Equal (_horizontal.Position, _horizontal.Size - _horizontal.Bounds.Width + 1);
+			Assert.Equal (_horizontal.Position, _hostView.Left);
+		}
+
+		[Fact]
+		public void KeepContentAlwaysInViewport_False ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			_vertical.KeepContentAlwaysInViewport = false;
+			_vertical.Position = 50;
+			Assert.Equal (_vertical.Position, _vertical.Size - 1);
+			Assert.Equal (_vertical.Position, _hostView.Top);
+
+			_horizontal.Position = 150;
+			Assert.Equal (_horizontal.Position, _horizontal.Size - 1);
+			Assert.Equal (_horizontal.Position, _hostView.Left);
+		}
+
+		[Fact]
+		public void AutoHideScrollBars_Check ()
+		{
+			Hosting_A_View_To_A_ScrollBarView ();
+
+			AddHandlers ();
+
+			_hostView.Lines = 10;
+			_hostView.Redraw (_hostView.Bounds);
+			Assert.False (_vertical.ShowScrollIndicator);
+			_hostView.Cols = 60;
+			_hostView.Redraw (_hostView.Bounds);
+			Assert.False (_horizontal.ShowScrollIndicator);
+
+			_hostView.Lines = 40;
+			_hostView.Redraw (_hostView.Bounds);
+			Assert.True (_vertical.ShowScrollIndicator);
+			_hostView.Cols = 120;
+			_hostView.Redraw (_hostView.Bounds);
+			Assert.True (_horizontal.ShowScrollIndicator);
+		}
+	}
+}