Index: tests/testapp/models/lookup.py
===================================================================
--- tests/testapp/models/lookup.py	(revision 1154)
+++ tests/testapp/models/lookup.py	(working copy)
@@ -103,4 +103,16 @@
 Article 4
 >>> a5.get_previous_by_pub_date()
 Article 6
+>>> a4.get_previous_by_pub_date()
+Article 3
+>>> a3.get_previous_by_pub_date()
+Article 2
+>>> a2.get_previous_by_pub_date()
+Article 1
+>>> a1.get_next_by_pub_date()
+Article 2
+>>> a2.get_next_by_pub_date()
+Article 3
+>>> a3.get_next_by_pub_date()
+Article 4
 """