changed test to ensure proper encoders/decoders are set

tests/ImageSharp.Tests/Formats/ImageFormatManagerTests.cs

@@ -8,9 +8,14 @@ using System.Linq;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Formats.Bmp;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Gif;
 using Moq;
 using Xunit;
 
+
 namespace SixLabors.ImageSharp.Tests
 {
     public class ImageFormatManagerTests
@@ -27,8 +32,15 @@ namespace SixLabors.ImageSharp.Tests
         [Fact]
         public void IfAutoloadWellKnownFormatsIsTrueAllFormatsAreLoaded()
         {
-            Assert.Equal(4, this.DefaultFormatsManager.ImageEncoders.Count());
+            Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<PngEncoder>().Count());
-            Assert.Equal(4, this.DefaultFormatsManager.ImageDecoders.Count());
+            Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<BmpEncoder>().Count());
+            Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<JpegEncoder>().Count());
+            Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<GifEncoder>().Count());
+
+            Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<PngDecoder>().Count());
+            Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<BmpDecoder>().Count());
+            Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<JpegDecoder>().Count());
+            Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<BmpDecoder>().Count());
         }
 
         [Fact]