diff --git a/converter.py b/converter.py
index d3eac5a44c8aadbfbb87323460aafd3b77084020..0c6ef0978e8317fc1344d086393a4dd6a2badc2f 100644
--- a/converter.py
+++ b/converter.py
@@ -89,6 +89,10 @@ class TestConverter(unittest.TestCase):
     def test_convertThousand(self):
         res = self.c.convert(1000)
         self.assertEqual(res, 'M')
+    
+    def test_convertFourDigit(self):
+        res = self.c.convert(1111)
+        self.assertEqual(res, 'MCXI')