diff --git a/Tests/images/color_snakes.png b/Tests/images/color_snakes.png
new file mode 100644
index 000000000..bf3a35196
Binary files /dev/null and b/Tests/images/color_snakes.png differ
diff --git a/Tests/test_imageops_usm.py b/Tests/test_imageops_usm.py
index ba65f211b..d1bdacd52 100644
--- a/Tests/test_imageops_usm.py
+++ b/Tests/test_imageops_usm.py
@@ -5,6 +5,7 @@ from PIL import ImageOps
 from PIL import ImageFilter
 
 im = Image.open("Tests/images/hopper.ppm")
+snakes = Image.open("Tests/images/color_snakes.png")
 
 
 class TestImageOpsUsm(PillowTestCase):
@@ -16,7 +17,7 @@ class TestImageOpsUsm(PillowTestCase):
         self.assertEqual(i.size, (128, 128))
         # i.save("blur.bmp")
 
-        i = ImageOps.usm(im, 2.0, 125, 8)
+        i = ImageOps.unsharp_mask(im, 2.0, 125, 8)
         self.assertEqual(i.mode, "RGB")
         self.assertEqual(i.size, (128, 128))
         # i.save("usm.bmp")
@@ -33,7 +34,7 @@ class TestImageOpsUsm(PillowTestCase):
         self.assertEqual(i.mode, "RGB")
         self.assertEqual(i.size, (128, 128))
 
-    def test_usm(self):
+    def test_usm_formats(self):
 
         usm = ImageOps.unsharp_mask
         self.assertRaises(ValueError, lambda: usm(im.convert("1")))
@@ -45,7 +46,7 @@ class TestImageOpsUsm(PillowTestCase):
         usm(im.convert("CMYK"))
         self.assertRaises(ValueError, lambda: usm(im.convert("YCbCr")))
 
-    def test_blur(self):
+    def test_blur_formats(self):
 
         blur = ImageOps.gaussian_blur
         self.assertRaises(ValueError, lambda: blur(im.convert("1")))
@@ -57,6 +58,33 @@ class TestImageOpsUsm(PillowTestCase):
         blur(im.convert("CMYK"))
         self.assertRaises(ValueError, lambda: blur(im.convert("YCbCr")))
 
+    def test_usm_accuracy(self):
+
+        i = snakes._new(ImageOps.unsharp_mask(snakes, 5, 1024, 0))
+        # Image should not be changed because it have only 0 and 255 levels.
+        self.assertEqual(i.tobytes(), snakes.tobytes())
+
+    def test_blur_accuracy(self):
+
+        i = snakes._new(ImageOps.gaussian_blur(snakes, .9))
+        # Alpha channel must match whole.
+        self.assertEqual(i.split()[3], snakes.split()[3])
+        # These pixels surrounded with pixels with 255 intensity.
+        # They must be 255.
+        for x, y, c in [(1, 0, 1), (2, 0, 1), (7, 8, 1), (8, 8, 1), (2, 9, 1),
+                        (7, 3, 0), (8, 3, 0), (5, 8, 0), (5, 9, 0), (1, 3, 0),
+                        (4, 3, 2), (4, 2, 2)]:
+            self.assertEqual(i.im.getpixel((x, y))[c], 255)
+        # Fuzzy match.
+        gp = lambda x, y: i.im.getpixel((x, y))
+        self.assertTrue(212 <= gp(7, 4)[0] <= 214)
+        self.assertTrue(212 <= gp(7, 5)[2] <= 214)
+        self.assertTrue(212 <= gp(7, 6)[2] <= 214)
+        self.assertTrue(212 <= gp(7, 7)[1] <= 214)
+        self.assertTrue(212 <= gp(8, 4)[0] <= 214)
+        self.assertTrue(212 <= gp(8, 5)[2] <= 214)
+        self.assertTrue(212 <= gp(8, 6)[2] <= 214)
+        self.assertTrue(212 <= gp(8, 7)[1] <= 214)
 
 if __name__ == '__main__':
     unittest.main()