diff --git a/src/gradients.rs b/src/gradients.rs
index 8a99ef2a..a8e93984 100644
--- a/src/gradients.rs
+++ b/src/gradients.rs
@@ -330,6 +330,8 @@ where
 #[cfg(test)]
 mod tests {
     use crate::filter::filter_clamped;
+    #[cfg(feature = "rayon")]
+    use crate::filter::filter_clamped_parallel;
 
     use super::*;
     use image::{ImageBuffer, Luma};
@@ -411,6 +413,23 @@ mod tests {
         assert_pixels_eq!(filtered, expected);
     }
 
+    #[test]
+    #[cfg(feature = "rayon")]
+    fn test_horizontal_sobel_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 2, 1;
+            6, 5, 4;
+            9, 8, 7);
+
+        let expected = gray_image!(type: i16,
+            -4, -8, -4;
+            -4, -8, -4;
+            -4, -8, -4);
+
+        let filtered = filter_clamped_parallel(&image, kernel::SOBEL_HORIZONTAL_3X3);
+        assert_pixels_eq!(filtered, expected);
+    }
+
     #[test]
     fn test_vertical_sobel_gradient_image() {
         let image = gray_image!(
@@ -427,6 +446,23 @@ mod tests {
         assert_pixels_eq!(filtered, expected);
     }
 
+    #[test]
+    #[cfg(feature = "rayon")]
+    fn test_vertical_sobel_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 6, 9;
+            2, 5, 8;
+            1, 4, 7);
+
+        let expected = gray_image!(type: i16,
+            -4, -4, -4;
+            -8, -8, -8;
+            -4, -4, -4);
+
+        let filtered = filter_clamped_parallel(&image, kernel::SOBEL_VERTICAL_3X3);
+        assert_pixels_eq!(filtered, expected);
+    }
+
     #[test]
     fn test_horizontal_scharr_gradient_image() {
         let image = gray_image!(
@@ -443,6 +479,23 @@ mod tests {
         assert_pixels_eq!(filtered, expected);
     }
 
+    #[test]
+    #[cfg(feature = "rayon")]
+    fn test_horizontal_scharr_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 2, 1;
+            6, 5, 4;
+            9, 8, 7);
+
+        let expected = gray_image!(type: i16,
+            -16, -32, -16;
+            -16, -32, -16;
+            -16, -32, -16);
+
+        let filtered = filter_clamped_parallel(&image, kernel::SCHARR_HORIZONTAL_3X3);
+        assert_pixels_eq!(filtered, expected);
+    }
+
     #[test]
     fn test_vertical_scharr_gradient_image() {
         let image = gray_image!(
@@ -459,6 +512,23 @@ mod tests {
         assert_pixels_eq!(filtered, expected);
     }
 
+    #[test]
+    #[cfg(feature = "rayon")]
+    fn test_vertical_scharr_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 6, 9;
+            2, 5, 8;
+            1, 4, 7);
+
+        let expected = gray_image!(type: i16,
+            -16, -16, -16;
+            -32, -32, -32;
+            -16, -16, -16);
+
+        let filtered = filter_clamped_parallel(&image, kernel::SCHARR_VERTICAL_3X3);
+        assert_pixels_eq!(filtered, expected);
+    }
+
     #[test]
     fn test_horizontal_prewitt_gradient_image() {
         let image = gray_image!(
@@ -476,6 +546,23 @@ mod tests {
     }
 
     #[test]
+    fn test_horizontal_prewitt_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 2, 1;
+            6, 5, 4;
+            9, 8, 7);
+
+        let expected = gray_image!(type: i16,
+            -3, -6, -3;
+            -3, -6, -3;
+            -3, -6, -3);
+
+        let filtered = filter_clamped_parallel(&image, kernel::PREWITT_HORIZONTAL_3X3);
+        assert_pixels_eq!(filtered, expected);
+    }
+
+    #[test]
+    #[cfg(feature = "rayon")]
     fn test_vertical_prewitt_gradient_image() {
         let image = gray_image!(
             3, 6, 9;
@@ -491,6 +578,23 @@ mod tests {
         assert_pixels_eq!(filtered, expected);
     }
 
+    #[test]
+    #[cfg(feature = "rayon")]
+    fn test_vertical_prewitt_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 6, 9;
+            2, 5, 8;
+            1, 4, 7);
+
+        let expected = gray_image!(type: i16,
+            -3, -3, -3;
+            -6, -6, -6;
+            -3, -3, -3);
+
+        let filtered = filter_clamped_parallel(&image, kernel::PREWITT_VERTICAL_3X3);
+        assert_pixels_eq!(filtered, expected);
+    }
+
     #[test]
     fn test_horizontal_roberts_gradient_image() {
         let image = gray_image!(
@@ -506,6 +610,24 @@ mod tests {
         let filtered = filter_clamped(&image, kernel::ROBERTS_HORIZONTAL_2X2);
         assert_pixels_eq!(filtered, expected);
     }
+
+    #[test]
+    #[cfg(feature = "rayon")]
+    fn test_horizontal_roberts_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 6, 9;
+            2, 5, 8;
+            1, 4, 7);
+
+        let expected = gray_image!(type: i16,
+            0, -3, -3;
+            1, -2, -2;
+            1, -2, -2);
+
+        let filtered = filter_clamped_parallel(&image, kernel::ROBERTS_HORIZONTAL_2X2);
+        assert_pixels_eq!(filtered, expected);
+    }
+
     #[test]
     fn test_vertical_roberts_gradient_image() {
         let image = gray_image!(
@@ -521,6 +643,23 @@ mod tests {
         let filtered = filter_clamped(&image, kernel::ROBERTS_VERTICAL_2X2);
         assert_pixels_eq!(filtered, expected);
     }
+
+    #[test]
+    #[cfg(feature = "rayon")]
+    fn test_vertical_roberts_gradient_image_parallel() {
+        let image = gray_image!(
+            3, 6, 9;
+            2, 5, 8;
+            1, 4, 7);
+
+        let expected = gray_image!(type: i16,
+            0, 3, 3;
+            1, 4, 4;
+            1, 4, 4);
+
+        let filtered = filter_clamped_parallel(&image, kernel::ROBERTS_VERTICAL_2X2);
+        assert_pixels_eq!(filtered, expected);
+    }
 }
 
 #[cfg(not(miri))]