diff --git a/ophyd/tests/test_utils.py b/ophyd/tests/test_utils.py
index 19c947774..3af8a7ace 100644
--- a/ophyd/tests/test_utils.py
+++ b/ophyd/tests/test_utils.py
@@ -156,7 +156,7 @@ def test_set_signal_to_None():
         [[1, 2, 3], 5, [], None, None, False],  # not the same type
         # numpy arrays
         [[1, 2, 3], np.array([1, 2, 3]), [], None, None, True],  # identical
-        [[1, 2, 3], np.array([1, 2, 3, 0]), [], None, None, True],  # only compares len(a) items
+        [[1, 2, 3], np.array([1, 2, 3, 0]), [], None, None, True],  # len(a)
         # tuple
         [(1, 2, 3), np.array([1, 2, 3]), [], None, None, True],  # identical
         # with tolerance