More tests

tests/Tests/GRContextTest.cs

@@ -34,5 +34,23 @@ namespace SkiaSharp.Tests
 				Assert.NotNull(grContext);
 			}
 		}
+
+		[Test]
+		public void GpuSurfaceIsCreated()
+		{
+			using (var ctx = CreateGlContext()) {
+				ctx.MakeCurrent();
+
+				using (var grContext = GRContext.Create(GRBackend.OpenGL))
+				using (var surface = SKSurface.Create(grContext, true, new SKImageInfo(100, 100))) {
+					Assert.NotNull(surface);
+
+					var canvas = surface.Canvas;
+					Assert.NotNull(canvas);
+
+					canvas.Clear(SKColors.Transparent);
+				}
+			}
+		}
 	}
 }

tests/Tests/SKCanvasTest.cs

@@ -0,0 +1,33 @@
+using System;
+using System.IO;
+using System.Linq;
+using NUnit.Framework;
+
+namespace SkiaSharp.Tests
+{
+	[Parallelizable(ParallelScope.None)]
+	public class SKCanvasTest : SKTest
+	{
+		[Test]
+		public void CanvasCanRestoreOnGpu()
+		{
+			using (var ctx = CreateGlContext()) {
+				ctx.MakeCurrent();
+
+				using (var grContext = GRContext.Create(GRBackend.OpenGL))
+				using (var surface = SKSurface.Create(grContext, true, new SKImageInfo(100, 100))) {
+					var canvas = surface.Canvas;
+
+					Assert.AreEqual(SKMatrix.MakeIdentity(), canvas.TotalMatrix);
+
+					using (new SKAutoCanvasRestore(canvas)) {
+						canvas.Translate(10, 10);
+						Assert.AreEqual(SKMatrix.MakeTranslation(10, 10), canvas.TotalMatrix);
+					}
+
+					Assert.AreEqual(SKMatrix.MakeIdentity(), canvas.TotalMatrix);
+				}
+			}
+		}
+	}
+}