diff --git a/tests/ImageSharp.Tests/Image/ImageFrameTests.cs b/tests/ImageSharp.Tests/Image/ImageFrameTests.cs
index d4aef75387..766bbd138a 100644
--- a/tests/ImageSharp.Tests/Image/ImageFrameTests.cs
+++ b/tests/ImageSharp.Tests/Image/ImageFrameTests.cs
@@ -16,7 +16,8 @@ namespace SixLabors.ImageSharp.Tests
 
             private void LimitBufferCapacity(int bufferCapacityInBytes)
             {
-                var allocator = (ArrayPoolMemoryAllocator)this.configuration.MemoryAllocator;
+                var allocator = ArrayPoolMemoryAllocator.CreateDefault();
+                this.configuration.MemoryAllocator = allocator;
                 allocator.BufferCapacityInBytes = bufferCapacityInBytes;
             }
 
diff --git a/tests/ImageSharp.Tests/Image/ImageTests.cs b/tests/ImageSharp.Tests/Image/ImageTests.cs
index 1296f26c47..db04794844 100644
--- a/tests/ImageSharp.Tests/Image/ImageTests.cs
+++ b/tests/ImageSharp.Tests/Image/ImageTests.cs
@@ -99,7 +99,8 @@ namespace SixLabors.ImageSharp.Tests
 
             private void LimitBufferCapacity(int bufferCapacityInBytes)
             {
-                var allocator = (ArrayPoolMemoryAllocator)this.configuration.MemoryAllocator;
+                var allocator = ArrayPoolMemoryAllocator.CreateDefault();
+                this.configuration.MemoryAllocator = allocator;
                 allocator.BufferCapacityInBytes = bufferCapacityInBytes;
             }
 
diff --git a/tests/ImageSharp.Tests/TestUtilities/ImageProviders/TestImageProvider.cs b/tests/ImageSharp.Tests/TestUtilities/ImageProviders/TestImageProvider.cs
index 700c40b726..4860524b36 100644
--- a/tests/ImageSharp.Tests/TestUtilities/ImageProviders/TestImageProvider.cs
+++ b/tests/ImageSharp.Tests/TestUtilities/ImageProviders/TestImageProvider.cs
@@ -21,11 +21,20 @@ namespace SixLabors.ImageSharp.Tests
     public abstract partial class TestImageProvider<TPixel> : ITestImageProvider, IXunitSerializable
         where TPixel : unmanaged, IPixel<TPixel>
     {
+        // Create a Configuration with Configuration.CreateDefaultInstance(),
+        // but use the shared MemoryAllocator from Configuration.Default.MemoryAllocator
+        private static Configuration CreateDefaultConfiguration()
+        {
+            var configuration = Configuration.CreateDefaultInstance();
+            configuration.MemoryAllocator = ImageSharp.Configuration.Default.MemoryAllocator;
+            return configuration;
+        }
+
         public PixelTypes PixelType { get; private set; } = typeof(TPixel).GetPixelType();
 
         public virtual string SourceFileOrDescription => string.Empty;
 
-        public Configuration Configuration { get; set; } = Configuration.CreateDefaultInstance();
+        public Configuration Configuration { get; set; } = CreateDefaultConfiguration();
 
         /// <summary>
         /// Gets the utility instance to provide information about the test image & manage input/output.
diff --git a/tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/MagickReferenceDecoder.cs b/tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/MagickReferenceDecoder.cs
index 294bd20fb5..f0834dc001 100644
--- a/tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/MagickReferenceDecoder.cs
+++ b/tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/MagickReferenceDecoder.cs
@@ -32,15 +32,15 @@ namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs
         private static void FromRgba32Bytes<TPixel>(Configuration configuration, Span<byte> rgbaBytes, IMemoryGroup<TPixel> destinationGroup)
             where TPixel : unmanaged, ImageSharp.PixelFormats.IPixel<TPixel>
         {
+            Span<Rgba32> sourcePixels = MemoryMarshal.Cast<byte, Rgba32>(rgbaBytes);
             foreach (Memory<TPixel> m in destinationGroup)
             {
                 Span<TPixel> destBuffer = m.Span;
-                PixelOperations<TPixel>.Instance.FromRgba32Bytes(
+                PixelOperations<TPixel>.Instance.FromRgba32(
                     configuration,
-                    rgbaBytes,
-                    destBuffer,
-                    destBuffer.Length);
-                rgbaBytes = rgbaBytes.Slice(destBuffer.Length * 4);
+                    sourcePixels.Slice(0, destBuffer.Length),
+                    destBuffer);
+                sourcePixels = sourcePixels.Slice(destBuffer.Length);
             }
         }
 
diff --git a/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs b/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs
index 26378796bd..3f41281d01 100644
--- a/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs
+++ b/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs
@@ -663,7 +663,8 @@ namespace SixLabors.ImageSharp.Tests
             this TestImageProvider<TPixel> provider)
             where TPixel : unmanaged, IPixel<TPixel>
         {
-            var allocator = (ArrayPoolMemoryAllocator)provider.Configuration.MemoryAllocator;
+            var allocator = ArrayPoolMemoryAllocator.CreateDefault();
+            provider.Configuration.MemoryAllocator = allocator;
             return new AllocatorBufferCapacityConfigurator(allocator, Unsafe.SizeOf<TPixel>());
         }