diff --git a/skimage/morphology/tests/test_watershed.py b/skimage/morphology/tests/test_watershed.py
index 660e9a9a..82531713 100644
--- a/skimage/morphology/tests/test_watershed.py
+++ b/skimage/morphology/tests/test_watershed.py
@@ -302,7 +302,7 @@ class TestWatershed(unittest.TestCase):
                          [255, 255, 255, 204, 204, 183, 153, 153, 153, 153, 183, 204, 204, 255, 255, 255],
                          [255, 255, 204, 183, 153, 141, 111, 103, 103, 111, 141, 153, 183, 204, 255, 255],
                          [255, 255, 204, 153, 111,  94,  72,  52,  52,  72,  94, 111, 153, 204, 255, 255],
-                         [255, 255, 204, 153, 111,  72,  39,   1,  1,  39,  72, 111, 153, 204, 255, 255],
+                         [255, 255, 204, 153, 111,  72,  39,   1,   1,  39,  72, 111, 153, 204, 255, 255],
                          [255, 255, 204, 183, 141, 111,  72,  39,  39,  72, 111, 141, 183, 204, 255, 255],
                          [255, 255, 255, 204, 183, 141, 111,  72,  72, 111, 141, 183, 204, 255, 255, 255],
                          [255, 255, 255, 255, 204, 183, 141,  94,  94, 141, 183, 204, 255, 255, 255, 255],