Add VectorMismatch tests

tests/ImageSharp.Tests/Formats/WebP/LosslessUtilsTests.cs

@@ -10,6 +10,24 @@ namespace SixLabors.ImageSharp.Tests.Formats.Webp
     [Trait("Format", "Webp")]
     public class LosslessUtilsTests
     {
+        private static void RunVectorMismatchTest()
+        {
+            uint[] array1 = { 4278193152, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896 };
+            uint[] array2 = { 4278193152, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896, 4278192896 };
+            int expected1 = 18;
+
+            // Test unroll first two loops path also.
+            uint[] array3 = { 4279238656, 4278714368, 4279238656, 4279238656, 4279238656, 4279238656, 4279238896, 4279238896, 4279238884 };
+            uint[] array4 = { 4279238656, 4278714368, 4279238656, 4279238656, 4278190080, 4278190080, 4278190080, 4278190080, 4278190080 };
+            int expected2 = 4;
+
+            int actual1 = LosslessUtils.VectorMismatch(array1, array2, 18);
+            int actual2 = LosslessUtils.VectorMismatch(array3, array4, 9);
+
+            Assert.Equal(expected1, actual1);
+            Assert.Equal(expected2, actual2);
+        }
+
         private static void RunSubtractGreenTest()
         {
             uint[] pixelData =
@@ -193,6 +211,9 @@ namespace SixLabors.ImageSharp.Tests.Formats.Webp
             }
         }
 
+        [Fact]
+        public void VectorMismatch_Works() => RunVectorMismatchTest();
+
         [Fact]
         public void Predictor11_Works() => RunPredictor11Test();
 
@@ -215,6 +236,12 @@ namespace SixLabors.ImageSharp.Tests.Formats.Webp
         public void TransformColorInverse_Works() => RunTransformColorInverseTest();
 
 #if SUPPORTS_RUNTIME_INTRINSICS
+        [Fact]
+        public void VectorMismatch_WithHardwareIntrinsics_Works() => FeatureTestRunner.RunWithHwIntrinsicsFeature(RunVectorMismatchTest, HwIntrinsics.AllowAll);
+
+        [Fact]
+        public void VectorMismatch_WithoutSSE2_Works() => FeatureTestRunner.RunWithHwIntrinsicsFeature(RunVectorMismatchTest, HwIntrinsics.DisableSSE2);
+
         [Fact]
         public void Predictor11_WithHardwareIntrinsics_Works() => FeatureTestRunner.RunWithHwIntrinsicsFeature(RunPredictor11Test, HwIntrinsics.AllowAll);