Apply @recoverable decorator to MySQLConnection.begin_transaction()

In the event that the connection has been lost, causing an
exception when the connection attempts to set the autoconnect mode,
the operation should be retried.

orator/connections/mysql_connection.py

@@ -2,7 +2,7 @@
 
 from ..utils import decode
 from ..utils import PY2
-from .connection import Connection
+from .connection import Connection, recoverable
 from ..query.grammars.mysql_grammar import MySQLQueryGrammar
 from ..query.processors.mysql_processor import MySQLQueryProcessor
 from ..schema.grammars import MySQLSchemaGrammar
@@ -37,6 +37,7 @@ def get_default_schema_grammar(self):
     def get_schema_manager(self):
         return MySQLSchemaManager(self)
 
+    @recoverable
     def begin_transaction(self):
         self._connection.autocommit(False)
 

tests/connections/test_mysql_connection.py

@@ -1,6 +1,9 @@
 # -*- coding: utf-8 -*-
 
+from flexmock import flexmock
+
 from .. import OratorTestCase
+from .. import mock
 
 from orator.connections.mysql_connection import MySQLConnection
 
@@ -20,3 +23,13 @@ def test_marker_use_qmark_false(self):
         connection = MySQLConnection(None, "database", "", {"use_qmark": False})
 
         self.assertIsNone(connection.get_marker())
+
+    def test_recover_if_caused_by_lost_connection_is_called(self):
+        connection = flexmock(MySQLConnection(None, "database"))
+        connection._connection = mock.Mock()
+        connection._connection.autocommit.side_effect = Exception("lost connection")
+
+        connection.should_receive("_recover_if_caused_by_lost_connection").once()
+        connection.should_receive("reconnect")
+
+        connection.begin_transaction()