Fix #194. Remove closed cursors from connnection

clickhouse_driver/dbapi/connection.py

@@ -88,6 +88,6 @@ def cursor(self):
             self._hosts = client.connection.hosts
         else:
             client.connection.hosts = self._hosts
-        cursor = Cursor(client)
+        cursor = Cursor(client, self)
         self.cursors.append(cursor)
         return cursor

clickhouse_driver/dbapi/cursor.py

@@ -23,8 +23,9 @@ class States(object):
 
     _states = States()
 
-    def __init__(self, client):
+    def __init__(self, client, connection):
         self._client = client
+        self._connection = connection
         self._reset_state()
 
         self.arraysize = 1
@@ -86,6 +87,12 @@ def close(self):
         self._client.disconnect()
         self._state = self._states.CURSOR_CLOSED
 
+        try:
+            # cursor can be already closed
+            self._connection.cursors.remove(self)
+        except ValueError:
+            pass
+
     def execute(self, operation, parameters=None):
         """
         Prepare and execute a database operation (query or command).

tests/test_dbapi.py

@@ -195,6 +195,14 @@ def side_getaddrinfo(host, *args, **kwargs):
         # once with host == 'wrong_host'.
         self.assertEqual(self.n_calls, 1)
 
+    def test_remove_cursor_from_connection_on_closing(self):
+        with self.created_connection() as connection:
+            self.assertEqual(len(connection.cursors), 0)
+            cur = connection.cursor()
+            self.assertEqual(len(connection.cursors), 1)
+            cur.close()
+            self.assertEqual(len(connection.cursors), 0)
+
 
 class StreamingTestCase(DBAPITestCaseBase):
     def test_fetchone(self):