From a3349efb34ae27ccc3b35fa632a66218c4c16fea Mon Sep 17 00:00:00 2001
From: Brian Popow <popow@gmx.de>
Date: Tue, 24 Mar 2026 11:31:07 +0100
Subject: [PATCH] Add ExrEncoder tests

---
 src/ImageSharp/Formats/Exr/ExrEncoderCore.cs  |  2 +-
 .../Formats/Exr/ExrEncoderTests.cs            | 58 +++++++++++++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 tests/ImageSharp.Tests/Formats/Exr/ExrEncoderTests.cs

diff --git a/src/ImageSharp/Formats/Exr/ExrEncoderCore.cs b/src/ImageSharp/Formats/Exr/ExrEncoderCore.cs
index a89caf07eb..e393dcf686 100644
--- a/src/ImageSharp/Formats/Exr/ExrEncoderCore.cs
+++ b/src/ImageSharp/Formats/Exr/ExrEncoderCore.cs
@@ -165,7 +165,7 @@ internal sealed class ExrEncoderCore
 
         using IMemoryOwner<float> rgbBuffer = this.memoryAllocator.Allocate<float>(width * 3, AllocationOptions.Clean);
         using IMemoryOwner<byte> rowBlockBuffer = this.memoryAllocator.Allocate<byte>((int)bytesPerBlock, AllocationOptions.Clean);
-        Span<float> redBuffer = rgbBuffer.GetSpan().Slice(0, width);
+        Span<float> redBuffer = rgbBuffer.GetSpan()[..width];
         Span<float> greenBuffer = rgbBuffer.GetSpan().Slice(width, width);
         Span<float> blueBuffer = rgbBuffer.GetSpan().Slice(width * 2, width);
 
diff --git a/tests/ImageSharp.Tests/Formats/Exr/ExrEncoderTests.cs b/tests/ImageSharp.Tests/Formats/Exr/ExrEncoderTests.cs
new file mode 100644
index 0000000000..b16c925f8a
--- /dev/null
+++ b/tests/ImageSharp.Tests/Formats/Exr/ExrEncoderTests.cs
@@ -0,0 +1,58 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Exr;
+using SixLabors.ImageSharp.Formats.Exr.Constants;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
+using SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
+
+namespace SixLabors.ImageSharp.Tests.Formats.Exr;
+
+[Trait("Format", "Exr")]
+[ValidateDisposedMemoryAllocations]
+public class ExrEncoderTests
+{
+    protected static readonly IImageDecoder ReferenceDecoder = new MagickReferenceDecoder(ExrFormat.Instance);
+
+    [Theory]
+    [WithFile(TestImages.Exr.Uncompressed, PixelTypes.Rgba32)]
+    public void ExrEncoder_WithNoCompression_Works<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel> => TestExrEncoderCore(provider, "NoCompression", compression: ExrCompression.None, imageDecoder: ExrDecoder.Instance);
+
+    [Theory]
+    [WithFile(TestImages.Exr.Uncompressed, PixelTypes.Rgba32)]
+    public void ExrEncoder_WithZipCompression_Works<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel> => TestExrEncoderCore(provider, "ZipCompression", compression: ExrCompression.Zip, imageDecoder: ExrDecoder.Instance);
+
+    [Theory]
+    [WithFile(TestImages.Exr.Uncompressed, PixelTypes.Rgba32)]
+    public void ExrEncoder_WithZipsCompression_Works<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel> => TestExrEncoderCore(provider, "ZipsCompression", compression: ExrCompression.Zips, imageDecoder: ExrDecoder.Instance);
+
+    protected static void TestExrEncoderCore<TPixel>(
+        TestImageProvider<TPixel> provider,
+        object testOutputDetails,
+        ExrCompression compression = ExrCompression.None,
+        bool useExactComparer = true,
+        float compareTolerance = 0.001f,
+        IImageDecoder imageDecoder = null)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage();
+        ExrEncoder encoder = new()
+        {
+            Compression = compression,
+        };
+
+        // Does DebugSave & load reference CompareToReferenceInput():
+        image.VerifyEncoder(
+            provider,
+            "exr",
+            testOutputDetails: testOutputDetails,
+            encoder: encoder,
+            customComparer: useExactComparer ? ImageComparer.Exact : ImageComparer.Tolerant(compareTolerance),
+            referenceDecoder: imageDecoder ?? ReferenceDecoder);
+    }
+}