Adds ImageExtensionsTest for gif.

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

@@ -0,0 +1,152 @@
+using System.IO;
+using System.Threading.Tasks;
+using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Gif;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests.Formats.Gif
+{
+    public class ImageExtensionsTest
+    {
+        [Fact]
+        public void SaveAsGif_Path()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensionsTest));
+            string file = Path.Combine(dir, "SaveAsGif_Path.gif");
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                image.SaveAsGif(file);
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsGifAsync_Path()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensionsTest));
+            string file = Path.Combine(dir, "SaveAsGifAsync_Path.gif");
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                await image.SaveAsGifAsync(file);
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public void SaveAsGif_Path_Encoder()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensions));
+            string file = Path.Combine(dir, "SaveAsGif_Path_Encoder.gif");
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                image.SaveAsGif(file, new GifEncoder());
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsGifAsync_Path_Encoder()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensions));
+            string file = Path.Combine(dir, "SaveAsGifAsync_Path_Encoder.gif");
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                await image.SaveAsGifAsync(file, new GifEncoder());
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public void SaveAsGif_Stream()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                image.SaveAsGif(memoryStream);
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsGifAsync_StreamAsync()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                await image.SaveAsGifAsync(memoryStream);
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public void SaveAsGif_Stream_Encoder()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                image.SaveAsGif(memoryStream, new GifEncoder());
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsGifAsync_Stream_Encoder()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<Rgba32>(10, 10))
+            {
+                await image.SaveAsGifAsync(memoryStream, new GifEncoder());
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/gif", mime.DefaultMimeType);
+            }
+        }
+    }
+}