diff --git a/fmn/lib/tests/example_rules.py b/fmn/lib/tests/example_rules.py
index 91169de..857b951 100644
--- a/fmn/lib/tests/example_rules.py
+++ b/fmn/lib/tests/example_rules.py
@@ -1,5 +1,7 @@
 """ Some example rules for the test suite. """
 
+import fmn.lib.hinting
+
 
 def wat_rule(config, message):
     return message['wat'] == 'blah'
@@ -7,3 +9,12 @@ def wat_rule(config, message):
 
 def not_wat_rule(config, message):
     return message['wat'] != 'blah'
+
+
+@fmn.lib.hinting.hint(categories=['whatever'])
+def hint_masked_rule(config, message, argument1):
+    """ This is a docstring.
+
+    For real, it is a docstring.
+    """
+    return True