Added extra unit tests.

tests/Magick.NET.Tests/Statistics/ChannelPerceptualHashTests/TheSumSquaredDistanceMethod.cs

@@ -0,0 +1,34 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+using ImageMagick;
+using Xunit;
+
+namespace Magick.NET.Tests;
+
+public partial class ChannelPerceptualHashTests
+{
+    public class TheToStringMethod
+    {
+        [Fact]
+        public void ShouldReturnTheCorrectValue()
+        {
+            using var image = new MagickImage(Files.ImageMagickJPG);
+            var phash = image.PerceptualHash();
+            Assert.NotNull(phash);
+
+            var red = phash.GetChannel(PixelChannel.Red);
+            var green = phash.GetChannel(PixelChannel.Green);
+            Assert.NotNull(red);
+            Assert.NotNull(green);
+
+#if Q8
+            OpenCLValue.Assert(13.33, 14.48, red.SumSquaredDistance(green));
+#elif Q16
+            OpenCLValue.Assert(23.02, 23.06, red.SumSquaredDistance(green));
+#else
+            OpenCLValue.Assert(29.99, 29.89, red.SumSquaredDistance(green));
+#endif
+        }
+    }
+}

tests/Magick.NET.Tests/Statistics/ChannelPerceptualHashTests/TheToStringMethod.cs

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+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+using ImageMagick;
+using Xunit;
+
+namespace Magick.NET.Tests;
+
+public partial class ChannelPerceptualHashTests
+{
+    public class TheSumSquaredDistanceMethod
+    {
+        [Fact]
+        public void ShouldReturnTheDifference()
+        {
+            //using var image = new MagickImage(Files.ImageMagickJPG);
+            using var image = new MagickImage(Files.FujiFilmFinePixS1ProJPG);
+            var phash = image.PerceptualHash();
+            Assert.NotNull(phash);
+
+            var red = phash.GetChannel(PixelChannel.Red);
+            Assert.NotNull(red);
+
+#if Q8
+            Assert.Equal("a65e687f9388c0e88f0261ce08eeb361d40a26ce81a1e823ec85b3b8cc3586ec889ad4", red.ToString());
+#elif Q16
+            Assert.Equal("a658c87fa088c0588eb561ccb8ed8a61d43a646682939835e986ec98c78f887ae8c67f", red.ToString());
+#else
+            Assert.Equal("a658c87fa188c0588eb561ccb8ed8861d43a731182e3a83aa2876d48d19488f438dcb5", red.ToString());
+#endif
+        }
+    }
+}