Additional testcases for gif decoder

Author: brianpopow

tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs

@@ -34,6 +34,41 @@ public void Decode_VerifyAllFrames<TPixel>(TestImageProvider<TPixel> provider)
         image.CompareToReferenceOutputMultiFrame(provider, ImageComparer.Exact);
     }
 
+    [Theory]
+    [WithFile(TestImages.Gif.AnimatedLoop, PixelTypes.Rgba32)]
+    [WithFile(TestImages.Gif.AnimatedLoopInterlaced, PixelTypes.Rgba32)]
+    public void Decode_Animated<TPixel>(TestImageProvider<TPixel> provider)
+    where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage();
+        image.DebugSaveMultiFrame(provider);
+        image.CompareToReferenceOutputMultiFrame(provider, ImageComparer.Exact);
+    }
+
+    [Theory]
+    [WithFile(TestImages.Gif.AnimatedTransparentNoRestore, PixelTypes.Rgba32)]
+    [WithFile(TestImages.Gif.AnimatedTransparentRestorePrevious, PixelTypes.Rgba32)]
+    [WithFile(TestImages.Gif.AnimatedTransparentLoop, PixelTypes.Rgba32)]
+    [WithFile(TestImages.Gif.AnimatedTransparentFirstFrameRestorePrev, PixelTypes.Rgba32)]
+    public void Decode_Animated_WithTransparency<TPixel>(TestImageProvider<TPixel> provider)
+    where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage();
+        image.DebugSaveMultiFrame(provider);
+        image.CompareToReferenceOutputMultiFrame(provider, ImageComparer.Exact);
+    }
+
+    [Theory]
+    [WithFile(TestImages.Gif.StaticNontransparent, PixelTypes.Rgba32)]
+    [WithFile(TestImages.Gif.StaticTransparent, PixelTypes.Rgba32)]
+    public void Decode_Static_No_Animation<TPixel>(TestImageProvider<TPixel> provider)
+    where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage();
+        image.DebugSave(provider);
+        image.CompareFirstFrameToReferenceOutput(ImageComparer.Exact, provider);
+    }
+
     [Theory]
     [WithFile(TestImages.Gif.Issues.Issue2450_A, PixelTypes.Rgba32)]
     [WithFile(TestImages.Gif.Issues.Issue2450_B, PixelTypes.Rgba32)]

tests/ImageSharp.Tests/TestImages.cs

@@ -507,6 +507,31 @@ public static class Gif
         public const string Bit18RGBCube = "Gif/18-bit_RGB_Cube.gif";
         public const string Global256NoTrans = "Gif/global-256-no-trans.gif";
 
+        // Test imagages from: https://github.com/peterdn/gif-test-suite.git
+        // Animated gif with 4 frames, looping forever, no transparency.
+        public const string AnimatedLoop = "Gif/animated_loop.gif";
+
+        // Animated gif with 4 frames, interlaced, looping forever, no transparency.
+        public const string AnimatedLoopInterlaced = "Gif/animated_loop_interlaced.gif";
+
+        // Transparent gif with 4 frames, loops forever.
+        public const string AnimatedTransparentLoop = "Gif/animated_transparent_loop.gif";
+
+        // Transparent gif with 4 frames, loops forever, first frame restore previous.
+        public const string AnimatedTransparentFirstFrameRestorePrev = "Gif/animated_transparent_firstframerestoreprev_loop.gif";
+
+        // Transparent gif with 4 transparent frames, loops forever, no dispose
+        public const string AnimatedTransparentNoRestore = "Gif/animated_transparent_frame_norestore_loop.gif";
+
+        // Transparent gif with 4 transparent frames, loops forever, restore previous.
+        public const string AnimatedTransparentRestorePrevious = "Gif/animated_transparent_frame_restoreprev_loop.gif";
+
+        // Static gif with no animation, no transparency.
+        public const string StaticNontransparent = "Gif/static_nontransparent.gif";
+
+        // Static transparent gif with no animation.
+        public const string StaticTransparent = "Gif/static_transparent.gif";
+
         // Test images from https://github.com/robert-ancell/pygif/tree/master/test-suite
         public const string ZeroSize = "Gif/image-zero-size.gif";
         public const string ZeroHeight = "Gif/image-zero-height.gif";