diff --git a/Tests/UnitTestsParallelizable/Drawing/LineCanvasTests.cs b/Tests/UnitTestsParallelizable/Drawing/LineCanvasTests.cs
new file mode 100644
index 000000000..d9c9cac9c
--- /dev/null
+++ b/Tests/UnitTestsParallelizable/Drawing/LineCanvasTests.cs
@@ -0,0 +1,401 @@
+namespace Terminal.Gui.DrawingTests;
+
+/// <summary>
+/// Tests for <see cref="LineCanvas"/>. All tests are parallelizable as they test LineCanvas directly
+/// without requiring Application.Driver or global state.
+/// </summary>
+public class LineCanvasTests : UnitTests.Parallelizable.ParallelizableBase
+{
+    #region Add_2_Lines Tests - Line Intersection Tests
+
+    [Theory]
+    // Horizontal lines with a vertical zero-length
+    [InlineData (0, 0, 1, Orientation.Horizontal, LineStyle.Double, 0, 0, 0, Orientation.Vertical, LineStyle.Single, "╞")]
+    [InlineData (0, 0, -1, Orientation.Horizontal, LineStyle.Double, 0, 0, 0, Orientation.Vertical, LineStyle.Single, "╡")]
+    [InlineData (0, 0, 1, Orientation.Horizontal, LineStyle.Single, 0, 0, 0, Orientation.Vertical, LineStyle.Double, "╟")]
+    [InlineData (0, 0, -1, Orientation.Horizontal, LineStyle.Single, 0, 0, 0, Orientation.Vertical, LineStyle.Double, "╢")]
+    [InlineData (0, 0, 1, Orientation.Horizontal, LineStyle.Single, 0, 0, 0, Orientation.Vertical, LineStyle.Single, "├")]
+    [InlineData (0, 0, -1, Orientation.Horizontal, LineStyle.Single, 0, 0, 0, Orientation.Vertical, LineStyle.Single, "┤")]
+    [InlineData (0, 0, 1, Orientation.Horizontal, LineStyle.Double, 0, 0, 0, Orientation.Vertical, LineStyle.Double, "╠")]
+    [InlineData (0, 0, -1, Orientation.Horizontal, LineStyle.Double, 0, 0, 0, Orientation.Vertical, LineStyle.Double, "╣")]
+    // Vertical lines with a horizontal zero-length
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Double, 0, 0, 1, Orientation.Vertical, LineStyle.Single, "╥")]
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Double, 0, 0, -1, Orientation.Vertical, LineStyle.Single, "╨")]
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Single, 0, 0, 1, Orientation.Vertical, LineStyle.Double, "╤")]
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Single, 0, 0, -1, Orientation.Vertical, LineStyle.Double, "╧")]
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Single, 0, 0, 1, Orientation.Vertical, LineStyle.Single, "┬")]
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Single, 0, 0, -1, Orientation.Vertical, LineStyle.Single, "┴")]
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Double, 0, 0, 1, Orientation.Vertical, LineStyle.Double, "╦")]
+    [InlineData (0, 0, 0, Orientation.Horizontal, LineStyle.Double, 0, 0, -1, Orientation.Vertical, LineStyle.Double, "╩")]
+    // Both zero-length (cross)
+    [InlineData (0, 0, 0, Orientation.Vertical, LineStyle.Single, 0, 0, 0, Orientation.Horizontal, LineStyle.Single, "┼")]
+    [InlineData (0, 0, 0, Orientation.Vertical, LineStyle.Double, 0, 0, 0, Orientation.Horizontal, LineStyle.Single, "╫")]
+    [InlineData (0, 0, 0, Orientation.Vertical, LineStyle.Single, 0, 0, 0, Orientation.Horizontal, LineStyle.Double, "╪")]
+    [InlineData (0, 0, 0, Orientation.Vertical, LineStyle.Double, 0, 0, 0, Orientation.Horizontal, LineStyle.Double, "╬")]
+    public void Add_2_Lines_Creates_Correct_Intersection (
+        int x1,
+        int y1,
+        int len1,
+        Orientation o1,
+        LineStyle s1,
+        int x2,
+        int y2,
+        int len2,
+        Orientation o2,
+        LineStyle s2,
+        string expected
+    )
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (x1, y1), len1, o1, s1);
+        canvas.AddLine (new Point (x2, y2), len2, o2, s2);
+
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    #endregion
+
+    #region Length Tests
+
+    [Theory]
+    [InlineData (0, 0, Orientation.Horizontal, "─")]
+    [InlineData (1, 0, Orientation.Horizontal, "─")]
+    [InlineData (0, 1, Orientation.Horizontal, "─")]
+    [InlineData (-1, 0, Orientation.Horizontal, "─")]
+    [InlineData (0, -1, Orientation.Horizontal, "─")]
+    [InlineData (-1, -1, Orientation.Horizontal, "─")]
+    [InlineData (0, 0, Orientation.Vertical, "│")]
+    [InlineData (1, 0, Orientation.Vertical, "│")]
+    [InlineData (0, 1, Orientation.Vertical, "│")]
+    [InlineData (0, -1, Orientation.Vertical, "│")]
+    [InlineData (-1, 0, Orientation.Vertical, "│")]
+    [InlineData (-1, -1, Orientation.Vertical, "│")]
+    public void Length_0_Creates_Single_Character_Line (int x, int y, Orientation orientation, string expected)
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (x, y), 0, orientation, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    [Theory]
+    [InlineData (0, 0, 1, Orientation.Horizontal, "─")]
+    [InlineData (1, 0, 1, Orientation.Horizontal, "─")]
+    [InlineData (0, 1, 1, Orientation.Horizontal, "─")]
+    [InlineData (0, 0, 1, Orientation.Vertical, "│")]
+    [InlineData (1, 0, 1, Orientation.Vertical, "│")]
+    [InlineData (0, 1, 1, Orientation.Vertical, "│")]
+    [InlineData (-1, 0, 1, Orientation.Horizontal, "─")]
+    [InlineData (0, -1, 1, Orientation.Horizontal, "─")]
+    [InlineData (-1, 0, 1, Orientation.Vertical, "│")]
+    [InlineData (0, -1, 1, Orientation.Vertical, "│")]
+    [InlineData (0, 0, 2, Orientation.Horizontal, "──")]
+    [InlineData (0, 0, 3, Orientation.Horizontal, "───")]
+    [InlineData (0, 0, 2, Orientation.Vertical, "│\n│")]
+    [InlineData (0, 0, 3, Orientation.Vertical, "│\n│\n│")]
+    public void Length_n_Creates_Line_Of_Length_n (int x, int y, int length, Orientation orientation, string expected)
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (x, y), length, orientation, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    [Fact]
+    public void Length_Negative_Creates_Line_In_Opposite_Direction ()
+    {
+        var canvas = new LineCanvas ();
+        
+        // Add a horizontal line from (2, 0) going left (negative length)
+        canvas.AddLine (new Point (2, 0), -3, Orientation.Horizontal, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal ("───", actual);
+    }
+
+    [Theory]
+    [InlineData (Orientation.Horizontal, "─")]
+    [InlineData (Orientation.Vertical, "│")]
+    public void Length_Zero_Alone_Creates_Single_Line (Orientation orientation, string expected)
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 0, orientation, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    [Theory]
+    [InlineData (Orientation.Horizontal, "┼")]
+    [InlineData (Orientation.Vertical, "┼")]
+    public void Length_Zero_Cross_Creates_Intersection (Orientation orientation, string expected)
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 0, Orientation.Horizontal, LineStyle.Single);
+        canvas.AddLine (new Point (0, 0), 0, orientation, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    [Theory]
+    [InlineData (Orientation.Horizontal, "┬")]
+    [InlineData (Orientation.Vertical, "├")]
+    public void Length_Zero_NextTo_Opposite_Creates_T (Orientation orientation, string expected)
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 1, Orientation.Horizontal, LineStyle.Single);
+        canvas.AddLine (new Point (0, 0), 0, orientation, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    #endregion
+
+    #region ToString Tests
+
+    [Fact]
+    public void ToString_Empty_Canvas_Returns_Empty_String ()
+    {
+        var canvas = new LineCanvas ();
+        Assert.Equal (string.Empty, canvas.ToString ());
+    }
+
+    [Theory]
+    [InlineData (0, 0, "─")]
+    [InlineData (1, 0, " ─")]
+    [InlineData (0, 1, "\n─")]
+    [InlineData (1, 1, "\n ─")]
+    [InlineData (2, 0, "  ─")]
+    [InlineData (2, 1, "\n  ─")]
+    [InlineData (0, 2, "\n\n─")]
+    [InlineData (2, 2, "\n\n  ─")]
+    public void ToString_Positive_Horizontal_1Line_With_Offset (int x, int y, string expected)
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (x, y), 1, Orientation.Horizontal, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    [Theory]
+    [InlineData (0, 0, "│")]
+    [InlineData (1, 0, " │")]
+    [InlineData (0, 1, "\n│")]
+    [InlineData (1, 1, "\n │")]
+    [InlineData (2, 0, "  │")]
+    [InlineData (2, 1, "\n  │")]
+    [InlineData (0, 2, "\n\n│")]
+    [InlineData (2, 2, "\n\n  │")]
+    public void ToString_Positive_Vertical_1Line_With_Offset (int x, int y, string expected)
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (x, y), 1, Orientation.Vertical, LineStyle.Single);
+        
+        string actual = canvas.ToString ();
+        Assert.Equal (expected, actual);
+    }
+
+    #endregion
+
+    #region Bounds Tests
+
+    [Fact]
+    public void Bounds_Empty_Canvas_Returns_Empty_Rectangle ()
+    {
+        var canvas = new LineCanvas ();
+        Assert.Equal (Rectangle.Empty, canvas.Bounds);
+    }
+
+    [Fact]
+    public void Bounds_Single_Point_Returns_1x1_Rectangle ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (5, 5), 0, Orientation.Horizontal, LineStyle.Single);
+        
+        Assert.Equal (new Rectangle (5, 5, 1, 1), canvas.Bounds);
+    }
+
+    [Fact]
+    public void Bounds_Horizontal_Line_Returns_Correct_Rectangle ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (2, 3), 5, Orientation.Horizontal, LineStyle.Single);
+        
+        Assert.Equal (new Rectangle (2, 3, 5, 1), canvas.Bounds);
+    }
+
+    [Fact]
+    public void Bounds_Vertical_Line_Returns_Correct_Rectangle ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (2, 3), 5, Orientation.Vertical, LineStyle.Single);
+        
+        Assert.Equal (new Rectangle (2, 3, 1, 5), canvas.Bounds);
+    }
+
+    [Fact]
+    public void Bounds_Multiple_Lines_Returns_Union ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 5, Orientation.Horizontal, LineStyle.Single);
+        canvas.AddLine (new Point (0, 0), 3, Orientation.Vertical, LineStyle.Single);
+        
+        Assert.Equal (new Rectangle (0, 0, 5, 3), canvas.Bounds);
+    }
+
+    [Fact]
+    public void Bounds_Negative_Length_Included ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (5, 5), -3, Orientation.Horizontal, LineStyle.Single);
+        
+        Assert.Equal (new Rectangle (2, 5, 3, 1), canvas.Bounds);
+    }
+
+    #endregion
+
+    #region Lines Property Tests
+
+    [Fact]
+    public void Lines_Empty_Canvas_Returns_Empty_Collection ()
+    {
+        var canvas = new LineCanvas ();
+        Assert.Empty (canvas.Lines);
+    }
+
+    [Fact]
+    public void Lines_Returns_Added_Lines ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 5, Orientation.Horizontal, LineStyle.Single);
+        canvas.AddLine (new Point (0, 0), 3, Orientation.Vertical, LineStyle.Double);
+        
+        Assert.Equal (2, canvas.Lines.Count);
+    }
+
+    [Fact]
+    public void Lines_Is_ReadOnly ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 5, Orientation.Horizontal, LineStyle.Single);
+        
+        Assert.IsAssignableFrom<IReadOnlyCollection<StraightLine>> (canvas.Lines);
+    }
+
+    #endregion
+
+    #region GetMap Tests
+
+    [Fact]
+    public void GetMap_Empty_Canvas_Returns_Empty_Dictionary ()
+    {
+        var canvas = new LineCanvas ();
+        var map = canvas.GetMap ();
+        
+        Assert.Empty (map);
+    }
+
+    [Fact]
+    public void GetMap_Single_Line_Returns_Correct_Points ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 3, Orientation.Horizontal, LineStyle.Single);
+        
+        var map = canvas.GetMap ();
+        
+        Assert.Equal (3, map.Count);
+        Assert.True (map.ContainsKey (new Point (0, 0)));
+        Assert.True (map.ContainsKey (new Point (1, 0)));
+        Assert.True (map.ContainsKey (new Point (2, 0)));
+    }
+
+    [Fact]
+    public void GetMap_Returns_Correct_Runes ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 3, Orientation.Horizontal, LineStyle.Single);
+        
+        var map = canvas.GetMap ();
+        
+        Assert.Equal (new System.Text.Rune ('─'), map [new Point (0, 0)]);
+        Assert.Equal (new System.Text.Rune ('─'), map [new Point (1, 0)]);
+        Assert.Equal (new System.Text.Rune ('─'), map [new Point (2, 0)]);
+    }
+
+    #endregion
+
+    #region Clear Tests
+
+    [Fact]
+    public void Clear_Removes_All_Lines ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 5, Orientation.Horizontal, LineStyle.Single);
+        canvas.AddLine (new Point (0, 0), 3, Orientation.Vertical, LineStyle.Single);
+        
+        canvas.Clear ();
+        
+        Assert.Empty (canvas.Lines);
+        Assert.Equal (Rectangle.Empty, canvas.Bounds);
+        Assert.Empty (canvas.GetMap ());
+    }
+
+    #endregion
+
+    #region AddLine Tests
+
+    [Fact]
+    public void AddLine_Adds_Line_To_Canvas ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 5, Orientation.Horizontal, LineStyle.Single);
+        
+        Assert.Single (canvas.Lines);
+    }
+
+    [Fact]
+    public void AddLine_Multiple_Times_Adds_All_Lines ()
+    {
+        var canvas = new LineCanvas ();
+        canvas.AddLine (new Point (0, 0), 5, Orientation.Horizontal, LineStyle.Single);
+        canvas.AddLine (new Point (0, 1), 5, Orientation.Horizontal, LineStyle.Single);
+        canvas.AddLine (new Point (0, 2), 5, Orientation.Horizontal, LineStyle.Single);
+        
+        Assert.Equal (3, canvas.Lines.Count);
+    }
+
+    #endregion
+
+    #region Constructor Tests
+
+    [Fact]
+    public void Constructor_Creates_Empty_Canvas ()
+    {
+        var canvas = new LineCanvas ();
+        
+        Assert.Empty (canvas.Lines);
+        Assert.Equal (Rectangle.Empty, canvas.Bounds);
+    }
+
+    [Fact]
+    public void Constructor_With_Lines_Creates_Canvas_With_Lines ()
+    {
+        var lines = new[]
+        {
+            new StraightLine (new Point (0, 0), 5, Orientation.Horizontal, LineStyle.Single),
+            new StraightLine (new Point (0, 0), 3, Orientation.Vertical, LineStyle.Single)
+        };
+        
+        var canvas = new LineCanvas (lines);
+        
+        Assert.Equal (2, canvas.Lines.Count);
+    }
+
+    #endregion
+}