diff --git a/tests/test_en.py b/tests/test_en.py
index 1508087..6234ac9 100644
--- a/tests/test_en.py
+++ b/tests/test_en.py
@@ -26,10 +26,18 @@ class Num2WordsENTest(TestCase):
         self.assertEqual(num2words(199), "one hundred and ninety-nine")
 
     def test_ordinal(self):
+        self.assertEqual(
+            num2words(0, lang='en', to='ordinal'),
+            'zeroth'
+        )
         self.assertEqual(
             num2words(1, lang='en', to='ordinal'),
             'first'
         )
+        self.assertEqual(
+            num2words(13, lang='en', to='ordinal'),
+            'thirteenth'
+        )
         self.assertEqual(
             num2words(22, lang='en', to='ordinal'),
             'twenty-second'