Use _binary prefix for bytes/bytearray parameters (#140)

- Based on #106 but now disabled by default
- Can be enabled via 'binary_prefix' connection parameter
- Added unit tests to verify behaviour

tests/test_MySQLdb_capabilities.py

@@ -2,10 +2,12 @@
 # -*- coding: utf-8 -*-
 import capabilities
 from datetime import timedelta
+from contextlib import closing
 import unittest
 import MySQLdb
 from MySQLdb.compat import unicode
 from MySQLdb import cursors
+from configdb import connection_factory
 import warnings
 
 
@@ -180,6 +182,23 @@ class test_MySQLdb(capabilities.DatabaseTest):
                 finally:
                     c.close()
 
+    def test_binary_prefix(self):
+        # verify prefix behaviour when enabled, disabled and for default (disabled)
+        for binary_prefix in (True, False, None):
+            kwargs = self.connect_kwargs.copy()
+            # needs to be set to can guarantee CHARSET response for normal strings
+            kwargs['charset'] = 'utf8'
+            if binary_prefix != None:
+                kwargs['binary_prefix'] = binary_prefix
+
+            with closing(connection_factory(**kwargs)) as conn:
+                with closing(conn.cursor()) as c:
+                    c.execute('SELECT CHARSET(%s)', (MySQLdb.Binary(b'raw bytes'),))
+                    self.assertEqual(c.fetchall()[0][0], 'binary' if binary_prefix else 'utf8')
+                    # normal strings should not get prefix
+                    c.execute('SELECT CHARSET(%s)', ('str',))
+                    self.assertEqual(c.fetchall()[0][0], 'utf8')
+
 
 if __name__ == '__main__':
     if test_MySQLdb.leak_test: