Fix issue comparing to wrong image in encode paletted color tiff tests

src/ImageSharp/Formats/Tiff/README.md

@@ -31,9 +31,6 @@ Decoder:
 - Decoding HUffman RLE for `Calliphora_huffman_rle.tiff` has 4 pixels difference to the reference decoder. Al those are at the very edge of the image (reason unknown so far).
 - Decoding compressed images with HorizontalPrediction: Works for deflate, but not for lzw.
 
-Encoder:
-- Encoding image with a palette have a difference of 0.0043% to the ReferenceDecoder (ImageMagick)
-
 ### Deviations from the TIFF spec (to be fixed)
 
 - Decoder

tests/ImageSharp.Tests/Formats/Tiff/TiffEncoderTests.cs

@@ -84,7 +84,6 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
             // Because a quantizer is used to create the palette (and therefore changes to the original are expected),
             // we do not compare the encoded image against the original:
             // Instead we load the encoded image with a reference decoder and compare against that image.
-            // TODO: There is a difference of 0,0043%
             using Image<TPixel> image = provider.GetImage();
             using var memStream = new MemoryStream();
             var encoder = new TiffEncoder { Mode = TiffEncodingMode.ColorPalette, Compression = TiffEncoderCompression.None };
@@ -93,8 +92,8 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
             memStream.Position = 0;
 
             using var encodedImage = (Image<TPixel>)Image.Load(memStream);
-            provider.Utility.SaveTestOutputFile(encodedImage, "tiff", encoder);
-            TiffTestUtils.CompareWithReferenceDecoder(provider, encodedImage);
+            var encodedImagePath = provider.Utility.SaveTestOutputFile(encodedImage, "tiff", encoder);
+            TiffTestUtils.CompareWithReferenceDecoder(encodedImagePath, encodedImage);
         }
 
         [Theory]
@@ -102,7 +101,6 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
         public void TiffEncoder_EncodeColorPalette_WithDeflateCompression_Works<TPixel>(TestImageProvider<TPixel> provider)
             where TPixel : unmanaged, IPixel<TPixel>
         {
-            // TODO: There is a difference of 0,0043%
             using Image<TPixel> image = provider.GetImage();
             using var memStream = new MemoryStream();
             var encoder = new TiffEncoder { Mode = TiffEncodingMode.ColorPalette, Compression = TiffEncoderCompression.Deflate };
@@ -111,8 +109,8 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
             memStream.Position = 0;
 
             using var encodedImage = (Image<TPixel>)Image.Load(memStream);
-            provider.Utility.SaveTestOutputFile(encodedImage, "tiff", encoder);
-            TiffTestUtils.CompareWithReferenceDecoder(provider, encodedImage);
+            var encodedImagePath = provider.Utility.SaveTestOutputFile(encodedImage, "tiff", encoder);
+            TiffTestUtils.CompareWithReferenceDecoder(encodedImagePath, encodedImage);
         }
 
         [Theory]
@@ -120,7 +118,6 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
         public void TiffEncoder_EncodeColorPalette_WithPackBitsCompression_Works<TPixel>(TestImageProvider<TPixel> provider)
             where TPixel : unmanaged, IPixel<TPixel>
         {
-            // TODO: There is a difference of 0,0043%
             using Image<TPixel> image = provider.GetImage();
             using var memStream = new MemoryStream();
             var encoder = new TiffEncoder { Mode = TiffEncodingMode.ColorPalette, Compression = TiffEncoderCompression.PackBits };
@@ -129,8 +126,8 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
             memStream.Position = 0;
 
             using var encodedImage = (Image<TPixel>)Image.Load(memStream);
-            provider.Utility.SaveTestOutputFile(encodedImage, "tiff", encoder);
-            TiffTestUtils.CompareWithReferenceDecoder(provider, encodedImage);
+            var encodedImagePath = provider.Utility.SaveTestOutputFile(encodedImage, "tiff", encoder);
+            TiffTestUtils.CompareWithReferenceDecoder(encodedImagePath, encodedImage);
         }
 
         [Theory]

tests/ImageSharp.Tests/Formats/Tiff/TiffTestUtils.cs

@@ -15,19 +15,13 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
     public static class TiffTestUtils
     {
         public static void CompareWithReferenceDecoder<TPixel>(
-            TestImageProvider<TPixel> provider,
+            string encodedImagePath,
             Image<TPixel> image,
             bool useExactComparer = true,
             float compareTolerance = 0.01f)
             where TPixel : unmanaged, ImageSharp.PixelFormats.IPixel<TPixel>
         {
-            string path = TestImageProvider<TPixel>.GetFilePathOrNull(provider);
-            if (path == null)
-            {
-                throw new InvalidOperationException("CompareToOriginal() works only with file providers!");
-            }
-
-            var testFile = TestFile.Create(path);
+            var testFile = TestFile.Create(encodedImagePath);
             Image<Rgba32> magickImage = DecodeWithMagick<Rgba32>(Configuration.Default, new FileInfo(testFile.FullPath));
             if (useExactComparer)
             {