diff --git a/gluon/tests/test_html.py b/gluon/tests/test_html.py
index a92cae55..f224a46c 100644
--- a/gluon/tests/test_html.py
+++ b/gluon/tests/test_html.py
@@ -233,6 +233,9 @@ class TestBareHelpers(unittest.TestCase):
'\n<>')
self.assertEqual(HTML('<>', _a='1', _b='2', doctype='').xml(),
'<>')
+ self.assertEqual(HTML('<>', _a='1', _b='2', doctype='CustomDocType').xml(),
+ 'CustomDocType\n<>')
+
def test_XHTML(self):
# Empty XHTML test