Merge pull request #23089 from mellinoe/system.drawing-drawstring-tests

Add two tests for Graphics.DrawString.
dotnet · Aug 10, 2017 · 277411f · 277411f
2 parents 47b0136 + f97a840
commit 277411f
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diff --git a/src/System.Drawing.Common/tests/GraphicsTests.cs b/src/System.Drawing.Common/tests/GraphicsTests.cs
@@ -8,6 +8,7 @@
 using System.Drawing.Text;
 using System.Linq;
 using Xunit;
+using Xunit.Sdk;
 
 namespace System.Drawing.Tests
 {
@@ -3460,6 +3461,32 @@ public void Clear_Disposed_ThrowsArgumentException()
             }
         }
 
+        [ActiveIssue(20884, TestPlatforms.AnyUnix)]
+        [ConditionalFact(Helpers.GdiplusIsAvailable)]
+        public void DrawString_DefaultFont_Succeeds()
+        {
+            using (var image = new Bitmap(50, 50))
+            using (Graphics graphics = Graphics.FromImage(image))
+            {
+                graphics.DrawString("Test text", SystemFonts.DefaultFont, Brushes.White, new Point());
+                Helpers.VerifyBitmapNotBlank(image);
+            }
+        }
+
+        [ActiveIssue(20884, TestPlatforms.AnyUnix)]
+        [ConditionalFact(Helpers.GdiplusIsAvailable)]
+        public void DrawString_CompositingModeSourceCopy_ThrowsArgumentException()
+        {
+            using (var image = new Bitmap(10, 10))
+            using (Graphics graphics = Graphics.FromImage(image))
+            {
+                graphics.CompositingMode = CompositingMode.SourceCopy;
+                AssertExtensions.Throws<ArgumentException>(
+                    null,
+                    () => graphics.DrawString("Test text", SystemFonts.DefaultFont, Brushes.White, new Point()));
+            }
+        }
+
         private static void VerifyGraphics(Graphics graphics, RectangleF expectedVisibleClipBounds)
         {
             Assert.NotNull(graphics.Clip);

diff --git a/src/System.Drawing.Common/tests/Helpers.cs b/src/System.Drawing.Common/tests/Helpers.cs
@@ -174,5 +174,23 @@ private struct RECT
             public int Right;
             public int Bottom;
         }
+
+        public static void VerifyBitmapNotBlank(Bitmap bmp)
+        {
+            Color emptyColor = Color.FromArgb(0);
+            for (int y = 0; y < bmp.Height; y++)
+            {
+                for (int x = 0; x < bmp.Width; x++)
+                {
+                    Color pixel = bmp.GetPixel(x, y);
+                    if (!pixel.Equals(emptyColor))
+                    {
+                        return;
+                    }
+                }
+            }
+
+            throw new XunitException("The entire image was blank.");
+        }
     }
 }