Refs #27683 -- Allowed setting isolation level in DATABASES ['OPTIONS'] on MySQL.

tests/backends/test_mysql.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 import unittest
 
+from django.core.exceptions import ImproperlyConfigured
 from django.db import connection
 from django.test import TestCase, override_settings
 
@@ -10,6 +11,12 @@ from django.test import TestCase, override_settings
 @unittest.skipUnless(connection.vendor == 'mysql', 'MySQL specific test.')
 class MySQLTests(TestCase):
 
+    @staticmethod
+    def get_isolation_level(connection):
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT @@session.tx_isolation")
+            return cursor.fetchone()[0]
+
     def test_auto_is_null_auto_config(self):
         query = 'set sql_auto_is_null = 0'
         connection.init_connection_state()
@@ -18,3 +25,42 @@ class MySQLTests(TestCase):
             self.assertIn(query, last_query)
         else:
             self.assertNotIn(query, last_query)
+
+    def test_connect_isolation_level(self):
+        read_committed = 'read committed'
+        repeatable_read = 'repeatable read'
+        isolation_values = {
+            level: level.replace(' ', '-').upper()
+            for level in (read_committed, repeatable_read)
+        }
+        configured_level = connection.isolation_level or isolation_values[repeatable_read]
+        configured_level = configured_level.upper()
+        other_level = read_committed if configured_level != isolation_values[read_committed] else repeatable_read
+
+        self.assertEqual(self.get_isolation_level(connection), configured_level)
+
+        new_connection = connection.copy()
+        new_connection.settings_dict['OPTIONS']['isolation_level'] = other_level
+        try:
+            self.assertEqual(self.get_isolation_level(new_connection), isolation_values[other_level])
+        finally:
+            new_connection.close()
+
+        # Upper case values are also accepted in 'isolation_level'.
+        new_connection = connection.copy()
+        new_connection.settings_dict['OPTIONS']['isolation_level'] = other_level.upper()
+        try:
+            self.assertEqual(self.get_isolation_level(new_connection), isolation_values[other_level])
+        finally:
+            new_connection.close()
+
+    def test_isolation_level_validation(self):
+        new_connection = connection.copy()
+        new_connection.settings_dict['OPTIONS']['isolation_level'] = 'xxx'
+        msg = (
+            "Invalid transaction isolation level 'xxx' specified.\n"
+            "Use one of 'read committed', 'read uncommitted', "
+            "'repeatable read', 'serializable', or None."
+        )
+        with self.assertRaisesMessage(ImproperlyConfigured, msg):
+            new_connection.cursor()