diff --git a/tests/test-doctest.py b/tests/test-doctest.py
--- a/tests/test-doctest.py
+++ b/tests/test-doctest.py
@@ -82,6 +82,7 @@
 testmod('mercurial.url')
 testmod('mercurial.util')
 testmod('mercurial.util', testtarget='platform')
+testmod('mercurial.utils.dateutil')
 testmod('mercurial.utils.stringutil')
 testmod('hgext.convert.convcmd')
 testmod('hgext.convert.cvsps')