diff --git a/testing/python/approx.py b/testing/python/approx.py
index 6a58cabfff3..91cb666c5da 100644
--- a/testing/python/approx.py
+++ b/testing/python/approx.py
@@ -778,6 +778,7 @@ def __array__(self, dtype=None, copy=None):
 
         vec1 = ImplicitArray([1.0, 2.0, 3.0])
         vec2 = ImplicitArray([1.0, 2.0, 4.0])
+        # see issue #12114 for test case
         assert vec1 != approx(vec2)
 
     def test_numpy_array_protocol(self):