diff --git a/pymysql/tests/test_connection.py b/pymysql/tests/test_connection.py
index f34f591..920f1e0 100644
--- a/pymysql/tests/test_connection.py
+++ b/pymysql/tests/test_connection.py
@@ -126,6 +126,7 @@ class TestConnection(base.PyMySQLTestCase):
             c = pymysql.connect(defer_connect=True, **d)
             self.assertFalse(c.open)
             c.connect(sock)
+            c.close()
 
 
 # A custom type and function to escape it