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django/tests/backends/base/test_base.py
Shai Berger d612026c37 Refs #28595 -- Added a hook to add execute wrappers for database queries.
Thanks Adam Johnson, Carl Meyer, Anssi Kääriäinen, Mariusz Felisiak,
Michael Manfre, and Tim Graham for discussion and review.
2017-09-21 12:13:09 -04:00

130 lines
5.4 KiB
Python

from unittest.mock import MagicMock
from django.db import DEFAULT_DB_ALIAS, connection, connections
from django.db.backends.base.base import BaseDatabaseWrapper
from django.test import SimpleTestCase, TestCase
from ..models import Square
class DatabaseWrapperTests(SimpleTestCase):
def test_initialization_class_attributes(self):
"""
The "initialization" class attributes like client_class and
creation_class should be set on the class and reflected in the
corresponding instance attributes of the instantiated backend.
"""
conn = connections[DEFAULT_DB_ALIAS]
conn_class = type(conn)
attr_names = [
('client_class', 'client'),
('creation_class', 'creation'),
('features_class', 'features'),
('introspection_class', 'introspection'),
('ops_class', 'ops'),
('validation_class', 'validation'),
]
for class_attr_name, instance_attr_name in attr_names:
class_attr_value = getattr(conn_class, class_attr_name)
self.assertIsNotNone(class_attr_value)
instance_attr_value = getattr(conn, instance_attr_name)
self.assertIsInstance(instance_attr_value, class_attr_value)
def test_initialization_display_name(self):
self.assertEqual(BaseDatabaseWrapper.display_name, 'unknown')
self.assertNotEqual(connection.display_name, 'unknown')
class ExecuteWrapperTests(TestCase):
@staticmethod
def call_execute(connection, params=None):
ret_val = '1' if params is None else '%s'
sql = 'SELECT ' + ret_val + connection.features.bare_select_suffix
with connection.cursor() as cursor:
cursor.execute(sql, params)
def call_executemany(self, connection, params=None):
# executemany() must use an update query. Make sure it does nothing
# by putting a false condition in the WHERE clause.
sql = 'DELETE FROM {} WHERE 0=1 AND 0=%s'.format(Square._meta.db_table)
if params is None:
params = [(i,) for i in range(3)]
with connection.cursor() as cursor:
cursor.executemany(sql, params)
@staticmethod
def mock_wrapper():
return MagicMock(side_effect=lambda execute, *args: execute(*args))
def test_wrapper_invoked(self):
wrapper = self.mock_wrapper()
with connection.execute_wrapper(wrapper):
self.call_execute(connection)
self.assertTrue(wrapper.called)
(_, sql, params, many, context), _ = wrapper.call_args
self.assertIn('SELECT', sql)
self.assertIsNone(params)
self.assertIs(many, False)
self.assertEqual(context['connection'], connection)
def test_wrapper_invoked_many(self):
wrapper = self.mock_wrapper()
with connection.execute_wrapper(wrapper):
self.call_executemany(connection)
self.assertTrue(wrapper.called)
(_, sql, param_list, many, context), _ = wrapper.call_args
self.assertIn('DELETE', sql)
self.assertIsInstance(param_list, (list, tuple))
self.assertIs(many, True)
self.assertEqual(context['connection'], connection)
def test_database_queried(self):
wrapper = self.mock_wrapper()
with connection.execute_wrapper(wrapper):
with connection.cursor() as cursor:
sql = 'SELECT 17' + connection.features.bare_select_suffix
cursor.execute(sql)
seventeen = cursor.fetchall()
self.assertEqual(list(seventeen), [(17,)])
self.call_executemany(connection)
def test_nested_wrapper_invoked(self):
outer_wrapper = self.mock_wrapper()
inner_wrapper = self.mock_wrapper()
with connection.execute_wrapper(outer_wrapper), connection.execute_wrapper(inner_wrapper):
self.call_execute(connection)
self.assertEqual(inner_wrapper.call_count, 1)
self.call_executemany(connection)
self.assertEqual(inner_wrapper.call_count, 2)
def test_outer_wrapper_blocks(self):
def blocker(*args):
pass
wrapper = self.mock_wrapper()
c = connection # This alias shortens the next line.
with c.execute_wrapper(wrapper), c.execute_wrapper(blocker), c.execute_wrapper(wrapper):
with c.cursor() as cursor:
cursor.execute("The database never sees this")
self.assertEqual(wrapper.call_count, 1)
cursor.executemany("The database never sees this %s", [("either",)])
self.assertEqual(wrapper.call_count, 2)
def test_wrapper_gets_sql(self):
wrapper = self.mock_wrapper()
sql = "SELECT 'aloha'" + connection.features.bare_select_suffix
with connection.execute_wrapper(wrapper), connection.cursor() as cursor:
cursor.execute(sql)
(_, reported_sql, _, _, _), _ = wrapper.call_args
self.assertEqual(reported_sql, sql)
def test_wrapper_connection_specific(self):
wrapper = self.mock_wrapper()
with connections['other'].execute_wrapper(wrapper):
self.assertEqual(connections['other'].execute_wrappers, [wrapper])
self.call_execute(connection)
self.assertFalse(wrapper.called)
self.assertEqual(connection.execute_wrappers, [])
self.assertEqual(connections['other'].execute_wrappers, [])