"""Tests related to django.db.backends that haven't been organized.""" import datetime import threading import unittest import warnings from django.core.management.color import no_style from django.db import ( DEFAULT_DB_ALIAS, DatabaseError, IntegrityError, connection, connections, reset_queries, transaction, ) from django.db.backends.base.base import BaseDatabaseWrapper from django.db.backends.signals import connection_created from django.db.backends.utils import CursorWrapper from django.db.models.sql.constants import CURSOR from django.test import ( TestCase, TransactionTestCase, override_settings, skipIfDBFeature, skipUnlessDBFeature, ) from .models import ( Article, Object, ObjectReference, Person, Post, RawData, Reporter, ReporterProxy, SchoolClass, Square, VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ, ) class DateQuotingTest(TestCase): def test_django_date_trunc(self): """ Test the custom ``django_date_trunc method``, in particular against fields which clash with strings passed to it (e.g. 'year') (#12818). """ updated = datetime.datetime(2010, 2, 20) SchoolClass.objects.create(year=2009, last_updated=updated) years = SchoolClass.objects.dates('last_updated', 'year') self.assertEqual(list(years), [datetime.date(2010, 1, 1)]) def test_django_date_extract(self): """ Test the custom ``django_date_extract method``, in particular against fields which clash with strings passed to it (e.g. 'day') (#12818). """ updated = datetime.datetime(2010, 2, 20) SchoolClass.objects.create(year=2009, last_updated=updated) classes = SchoolClass.objects.filter(last_updated__day=20) self.assertEqual(len(classes), 1) @override_settings(DEBUG=True) class LastExecutedQueryTest(TestCase): def test_last_executed_query_without_previous_query(self): """ last_executed_query should not raise an exception even if no previous query has been run. """ with connection.cursor() as cursor: connection.ops.last_executed_query(cursor, '', ()) def test_debug_sql(self): list(Reporter.objects.filter(first_name="test")) sql = connection.queries[-1]['sql'].lower() self.assertIn("select", sql) self.assertIn(Reporter._meta.db_table, sql) def test_query_encoding(self): """last_executed_query() returns a string.""" data = RawData.objects.filter(raw_data=b'\x00\x46 \xFE').extra(select={'föö': 1}) sql, params = data.query.sql_with_params() with data.query.get_compiler('default').execute_sql(CURSOR) as cursor: last_sql = cursor.db.ops.last_executed_query(cursor, sql, params) self.assertIsInstance(last_sql, str) def test_last_executed_query(self): # last_executed_query() interpolate all parameters, in most cases it is # not equal to QuerySet.query. for qs in ( Article.objects.filter(pk=1), Article.objects.filter(pk__in=(1, 2), reporter__pk=3), Article.objects.filter( pk=1, reporter__pk=9, ).exclude(reporter__pk__in=[2, 1]), ): sql, params = qs.query.sql_with_params() with qs.query.get_compiler(DEFAULT_DB_ALIAS).execute_sql(CURSOR) as cursor: self.assertEqual( cursor.db.ops.last_executed_query(cursor, sql, params), str(qs.query), ) @skipUnlessDBFeature('supports_paramstyle_pyformat') def test_last_executed_query_dict(self): square_opts = Square._meta sql = 'INSERT INTO %s (%s, %s) VALUES (%%(root)s, %%(square)s)' % ( connection.introspection.identifier_converter(square_opts.db_table), connection.ops.quote_name(square_opts.get_field('root').column), connection.ops.quote_name(square_opts.get_field('square').column), ) with connection.cursor() as cursor: params = {'root': 2, 'square': 4} cursor.execute(sql, params) self.assertEqual( cursor.db.ops.last_executed_query(cursor, sql, params), sql % params, ) class ParameterHandlingTest(TestCase): def test_bad_parameter_count(self): "An executemany call with too many/not enough parameters will raise an exception (Refs #12612)" with connection.cursor() as cursor: query = ('INSERT INTO %s (%s, %s) VALUES (%%s, %%s)' % ( connection.introspection.identifier_converter('backends_square'), connection.ops.quote_name('root'), connection.ops.quote_name('square') )) with self.assertRaises(Exception): cursor.executemany(query, [(1, 2, 3)]) with self.assertRaises(Exception): cursor.executemany(query, [(1,)]) class LongNameTest(TransactionTestCase): """Long primary keys and model names can result in a sequence name that exceeds the database limits, which will result in truncation on certain databases (e.g., Postgres). The backend needs to use the correct sequence name in last_insert_id and other places, so check it is. Refs #8901. """ available_apps = ['backends'] def test_sequence_name_length_limits_create(self): """Test creation of model with long name and long pk name doesn't error. Ref #8901""" VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.objects.create() def test_sequence_name_length_limits_m2m(self): """ An m2m save of a model with a long name and a long m2m field name doesn't error (#8901). """ obj = VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.objects.create() rel_obj = Person.objects.create(first_name='Django', last_name='Reinhardt') obj.m2m_also_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz.add(rel_obj) def test_sequence_name_length_limits_flush(self): """ Sequence resetting as part of a flush with model with long name and long pk name doesn't error (#8901). """ # A full flush is expensive to the full test, so we dig into the # internals to generate the likely offending SQL and run it manually # Some convenience aliases VLM = VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ VLM_m2m = VLM.m2m_also_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz.through tables = [ VLM._meta.db_table, VLM_m2m._meta.db_table, ] sql_list = connection.ops.sql_flush(no_style(), tables, reset_sequences=True) connection.ops.execute_sql_flush(sql_list) class SequenceResetTest(TestCase): def test_generic_relation(self): "Sequence names are correct when resetting generic relations (Ref #13941)" # Create an object with a manually specified PK Post.objects.create(id=10, name='1st post', text='hello world') # Reset the sequences for the database commands = connections[DEFAULT_DB_ALIAS].ops.sequence_reset_sql(no_style(), [Post]) with connection.cursor() as cursor: for sql in commands: cursor.execute(sql) # If we create a new object now, it should have a PK greater # than the PK we specified manually. obj = Post.objects.create(name='New post', text='goodbye world') self.assertGreater(obj.pk, 10) # This test needs to run outside of a transaction, otherwise closing the # connection would implicitly rollback and cause problems during teardown. class ConnectionCreatedSignalTest(TransactionTestCase): available_apps = [] # Unfortunately with sqlite3 the in-memory test database cannot be closed, # and so it cannot be re-opened during testing. @skipUnlessDBFeature('test_db_allows_multiple_connections') def test_signal(self): data = {} def receiver(sender, connection, **kwargs): data["connection"] = connection connection_created.connect(receiver) connection.close() with connection.cursor(): pass self.assertIs(data["connection"].connection, connection.connection) connection_created.disconnect(receiver) data.clear() with connection.cursor(): pass self.assertEqual(data, {}) class EscapingChecks(TestCase): """ All tests in this test case are also run with settings.DEBUG=True in EscapingChecksDebug test case, to also test CursorDebugWrapper. """ bare_select_suffix = connection.features.bare_select_suffix def test_paramless_no_escaping(self): with connection.cursor() as cursor: cursor.execute("SELECT '%s'" + self.bare_select_suffix) self.assertEqual(cursor.fetchall()[0][0], '%s') def test_parameter_escaping(self): with connection.cursor() as cursor: cursor.execute("SELECT '%%', %s" + self.bare_select_suffix, ('%d',)) self.assertEqual(cursor.fetchall()[0], ('%', '%d')) @override_settings(DEBUG=True) class EscapingChecksDebug(EscapingChecks): pass class BackendTestCase(TransactionTestCase): available_apps = ['backends'] def create_squares_with_executemany(self, args): self.create_squares(args, 'format', True) def create_squares(self, args, paramstyle, multiple): opts = Square._meta tbl = connection.introspection.identifier_converter(opts.db_table) f1 = connection.ops.quote_name(opts.get_field('root').column) f2 = connection.ops.quote_name(opts.get_field('square').column) if paramstyle == 'format': query = 'INSERT INTO %s (%s, %s) VALUES (%%s, %%s)' % (tbl, f1, f2) elif paramstyle == 'pyformat': query = 'INSERT INTO %s (%s, %s) VALUES (%%(root)s, %%(square)s)' % (tbl, f1, f2) else: raise ValueError("unsupported paramstyle in test") with connection.cursor() as cursor: if multiple: cursor.executemany(query, args) else: cursor.execute(query, args) def test_cursor_executemany(self): # Test cursor.executemany #4896 args = [(i, i ** 2) for i in range(-5, 6)] self.create_squares_with_executemany(args) self.assertEqual(Square.objects.count(), 11) for i in range(-5, 6): square = Square.objects.get(root=i) self.assertEqual(square.square, i ** 2) def test_cursor_executemany_with_empty_params_list(self): # Test executemany with params=[] does nothing #4765 args = [] self.create_squares_with_executemany(args) self.assertEqual(Square.objects.count(), 0) def test_cursor_executemany_with_iterator(self): # Test executemany accepts iterators #10320 args = ((i, i ** 2) for i in range(-3, 2)) self.create_squares_with_executemany(args) self.assertEqual(Square.objects.count(), 5) args = ((i, i ** 2) for i in range(3, 7)) with override_settings(DEBUG=True): # same test for DebugCursorWrapper self.create_squares_with_executemany(args) self.assertEqual(Square.objects.count(), 9) @skipUnlessDBFeature('supports_paramstyle_pyformat') def test_cursor_execute_with_pyformat(self): # Support pyformat style passing of parameters #10070 args = {'root': 3, 'square': 9} self.create_squares(args, 'pyformat', multiple=False) self.assertEqual(Square.objects.count(), 1) @skipUnlessDBFeature('supports_paramstyle_pyformat') def test_cursor_executemany_with_pyformat(self): # Support pyformat style passing of parameters #10070 args = [{'root': i, 'square': i ** 2} for i in range(-5, 6)] self.create_squares(args, 'pyformat', multiple=True) self.assertEqual(Square.objects.count(), 11) for i in range(-5, 6): square = Square.objects.get(root=i) self.assertEqual(square.square, i ** 2) @skipUnlessDBFeature('supports_paramstyle_pyformat') def test_cursor_executemany_with_pyformat_iterator(self): args = ({'root': i, 'square': i ** 2} for i in range(-3, 2)) self.create_squares(args, 'pyformat', multiple=True) self.assertEqual(Square.objects.count(), 5) args = ({'root': i, 'square': i ** 2} for i in range(3, 7)) with override_settings(DEBUG=True): # same test for DebugCursorWrapper self.create_squares(args, 'pyformat', multiple=True) self.assertEqual(Square.objects.count(), 9) def test_unicode_fetches(self): # fetchone, fetchmany, fetchall return strings as Unicode objects. qn = connection.ops.quote_name Person(first_name="John", last_name="Doe").save() Person(first_name="Jane", last_name="Doe").save() Person(first_name="Mary", last_name="Agnelline").save() Person(first_name="Peter", last_name="Parker").save() Person(first_name="Clark", last_name="Kent").save() opts2 = Person._meta f3, f4 = opts2.get_field('first_name'), opts2.get_field('last_name') with connection.cursor() as cursor: cursor.execute( 'SELECT %s, %s FROM %s ORDER BY %s' % ( qn(f3.column), qn(f4.column), connection.introspection.identifier_converter(opts2.db_table), qn(f3.column), ) ) self.assertEqual(cursor.fetchone(), ('Clark', 'Kent')) self.assertEqual(list(cursor.fetchmany(2)), [('Jane', 'Doe'), ('John', 'Doe')]) self.assertEqual(list(cursor.fetchall()), [('Mary', 'Agnelline'), ('Peter', 'Parker')]) def test_unicode_password(self): old_password = connection.settings_dict['PASSWORD'] connection.settings_dict['PASSWORD'] = "françois" try: with connection.cursor(): pass except DatabaseError: # As password is probably wrong, a database exception is expected pass except Exception as e: self.fail('Unexpected error raised with Unicode password: %s' % e) finally: connection.settings_dict['PASSWORD'] = old_password def test_database_operations_helper_class(self): # Ticket #13630 self.assertTrue(hasattr(connection, 'ops')) self.assertTrue(hasattr(connection.ops, 'connection')) self.assertEqual(connection, connection.ops.connection) def test_database_operations_init(self): """ DatabaseOperations initialization doesn't query the database. See #17656. """ with self.assertNumQueries(0): connection.ops.__class__(connection) def test_cached_db_features(self): self.assertIn(connection.features.supports_transactions, (True, False)) self.assertIn(connection.features.can_introspect_foreign_keys, (True, False)) def test_duplicate_table_error(self): """ Creating an existing table returns a DatabaseError """ query = 'CREATE TABLE %s (id INTEGER);' % Article._meta.db_table with connection.cursor() as cursor: with self.assertRaises(DatabaseError): cursor.execute(query) def test_cursor_contextmanager(self): """ Cursors can be used as a context manager """ with connection.cursor() as cursor: self.assertIsInstance(cursor, CursorWrapper) # Both InterfaceError and ProgrammingError seem to be used when # accessing closed cursor (psycopg2 has InterfaceError, rest seem # to use ProgrammingError). with self.assertRaises(connection.features.closed_cursor_error_class): # cursor should be closed, so no queries should be possible. cursor.execute("SELECT 1" + connection.features.bare_select_suffix) @unittest.skipUnless(connection.vendor == 'postgresql', "Psycopg2 specific cursor.closed attribute needed") def test_cursor_contextmanager_closing(self): # There isn't a generic way to test that cursors are closed, but # psycopg2 offers us a way to check that by closed attribute. # So, run only on psycopg2 for that reason. with connection.cursor() as cursor: self.assertIsInstance(cursor, CursorWrapper) self.assertTrue(cursor.closed) # Unfortunately with sqlite3 the in-memory test database cannot be closed. @skipUnlessDBFeature('test_db_allows_multiple_connections') def test_is_usable_after_database_disconnects(self): """ is_usable() doesn't crash when the database disconnects (#21553). """ # Open a connection to the database. with connection.cursor(): pass # Emulate a connection close by the database. connection._close() # Even then is_usable() should not raise an exception. try: self.assertFalse(connection.is_usable()) finally: # Clean up the mess created by connection._close(). Since the # connection is already closed, this crashes on some backends. try: connection.close() except Exception: pass @override_settings(DEBUG=True) def test_queries(self): """ Test the documented API of connection.queries. """ sql = 'SELECT 1' + connection.features.bare_select_suffix with connection.cursor() as cursor: reset_queries() cursor.execute(sql) self.assertEqual(1, len(connection.queries)) self.assertIsInstance(connection.queries, list) self.assertIsInstance(connection.queries[0], dict) self.assertEqual(list(connection.queries[0]), ['sql', 'time']) self.assertEqual(connection.queries[0]['sql'], sql) reset_queries() self.assertEqual(0, len(connection.queries)) sql = ('INSERT INTO %s (%s, %s) VALUES (%%s, %%s)' % ( connection.introspection.identifier_converter('backends_square'), connection.ops.quote_name('root'), connection.ops.quote_name('square'), )) with connection.cursor() as cursor: cursor.executemany(sql, [(1, 1), (2, 4)]) self.assertEqual(1, len(connection.queries)) self.assertIsInstance(connection.queries, list) self.assertIsInstance(connection.queries[0], dict) self.assertEqual(list(connection.queries[0]), ['sql', 'time']) self.assertEqual(connection.queries[0]['sql'], '2 times: %s' % sql) # Unfortunately with sqlite3 the in-memory test database cannot be closed. @skipUnlessDBFeature('test_db_allows_multiple_connections') @override_settings(DEBUG=True) def test_queries_limit(self): """ The backend doesn't store an unlimited number of queries (#12581). """ old_queries_limit = BaseDatabaseWrapper.queries_limit BaseDatabaseWrapper.queries_limit = 3 new_connection = connection.copy() # Initialize the connection and clear initialization statements. with new_connection.cursor(): pass new_connection.queries_log.clear() try: with new_connection.cursor() as cursor: cursor.execute("SELECT 1" + new_connection.features.bare_select_suffix) cursor.execute("SELECT 2" + new_connection.features.bare_select_suffix) with warnings.catch_warnings(record=True) as w: self.assertEqual(2, len(new_connection.queries)) self.assertEqual(0, len(w)) with new_connection.cursor() as cursor: cursor.execute("SELECT 3" + new_connection.features.bare_select_suffix) cursor.execute("SELECT 4" + new_connection.features.bare_select_suffix) msg = "Limit for query logging exceeded, only the last 3 queries will be returned." with self.assertWarnsMessage(UserWarning, msg): self.assertEqual(3, len(new_connection.queries)) finally: BaseDatabaseWrapper.queries_limit = old_queries_limit new_connection.close() def test_timezone_none_use_tz_false(self): connection.ensure_connection() with self.settings(TIME_ZONE=None, USE_TZ=False): connection.init_connection_state() # These tests aren't conditional because it would require differentiating # between MySQL+InnoDB and MySQL+MYISAM (something we currently can't do). class FkConstraintsTests(TransactionTestCase): available_apps = ['backends'] def setUp(self): # Create a Reporter. self.r = Reporter.objects.create(first_name='John', last_name='Smith') def test_integrity_checks_on_creation(self): """ Try to create a model instance that violates a FK constraint. If it fails it should fail with IntegrityError. """ a1 = Article(headline="This is a test", pub_date=datetime.datetime(2005, 7, 27), reporter_id=30) try: a1.save() except IntegrityError: pass else: self.skipTest("This backend does not support integrity checks.") # Now that we know this backend supports integrity checks we make sure # constraints are also enforced for proxy Refs #17519 a2 = Article( headline='This is another test', reporter=self.r, pub_date=datetime.datetime(2012, 8, 3), reporter_proxy_id=30, ) with self.assertRaises(IntegrityError): a2.save() def test_integrity_checks_on_update(self): """ Try to update a model instance introducing a FK constraint violation. If it fails it should fail with IntegrityError. """ # Create an Article. Article.objects.create(headline="Test article", pub_date=datetime.datetime(2010, 9, 4), reporter=self.r) # Retrieve it from the DB a1 = Article.objects.get(headline="Test article") a1.reporter_id = 30 try: a1.save() except IntegrityError: pass else: self.skipTest("This backend does not support integrity checks.") # Now that we know this backend supports integrity checks we make sure # constraints are also enforced for proxy Refs #17519 # Create another article r_proxy = ReporterProxy.objects.get(pk=self.r.pk) Article.objects.create( headline='Another article', pub_date=datetime.datetime(1988, 5, 15), reporter=self.r, reporter_proxy=r_proxy, ) # Retrieve the second article from the DB a2 = Article.objects.get(headline='Another article') a2.reporter_proxy_id = 30 with self.assertRaises(IntegrityError): a2.save() def test_disable_constraint_checks_manually(self): """ When constraint checks are disabled, should be able to write bad data without IntegrityErrors. """ with transaction.atomic(): # Create an Article. Article.objects.create( headline="Test article", pub_date=datetime.datetime(2010, 9, 4), reporter=self.r, ) # Retrieve it from the DB a = Article.objects.get(headline="Test article") a.reporter_id = 30 try: connection.disable_constraint_checking() a.save() connection.enable_constraint_checking() except IntegrityError: self.fail("IntegrityError should not have occurred.") transaction.set_rollback(True) def test_disable_constraint_checks_context_manager(self): """ When constraint checks are disabled (using context manager), should be able to write bad data without IntegrityErrors. """ with transaction.atomic(): # Create an Article. Article.objects.create( headline="Test article", pub_date=datetime.datetime(2010, 9, 4), reporter=self.r, ) # Retrieve it from the DB a = Article.objects.get(headline="Test article") a.reporter_id = 30 try: with connection.constraint_checks_disabled(): a.save() except IntegrityError: self.fail("IntegrityError should not have occurred.") transaction.set_rollback(True) def test_check_constraints(self): """ Constraint checks should raise an IntegrityError when bad data is in the DB. """ with transaction.atomic(): # Create an Article. Article.objects.create( headline="Test article", pub_date=datetime.datetime(2010, 9, 4), reporter=self.r, ) # Retrieve it from the DB a = Article.objects.get(headline="Test article") a.reporter_id = 30 with connection.constraint_checks_disabled(): a.save() with self.assertRaises(IntegrityError): connection.check_constraints() transaction.set_rollback(True) class ThreadTests(TransactionTestCase): available_apps = ['backends'] def test_default_connection_thread_local(self): """ The default connection (i.e. django.db.connection) is different for each thread (#17258). """ # Map connections by id because connections with identical aliases # have the same hash. connections_dict = {} with connection.cursor(): pass connections_dict[id(connection)] = connection def runner(): # Passing django.db.connection between threads doesn't work while # connections[DEFAULT_DB_ALIAS] does. from django.db import connections connection = connections[DEFAULT_DB_ALIAS] # Allow thread sharing so the connection can be closed by the # main thread. connection.inc_thread_sharing() with connection.cursor(): pass connections_dict[id(connection)] = connection try: for x in range(2): t = threading.Thread(target=runner) t.start() t.join() # Each created connection got different inner connection. self.assertEqual(len({conn.connection for conn in connections_dict.values()}), 3) finally: # Finish by closing the connections opened by the other threads # (the connection opened in the main thread will automatically be # closed on teardown). for conn in connections_dict.values(): if conn is not connection: if conn.allow_thread_sharing: conn.close() conn.dec_thread_sharing() def test_connections_thread_local(self): """ The connections are different for each thread (#17258). """ # Map connections by id because connections with identical aliases # have the same hash. connections_dict = {} for conn in connections.all(): connections_dict[id(conn)] = conn def runner(): from django.db import connections for conn in connections.all(): # Allow thread sharing so the connection can be closed by the # main thread. conn.inc_thread_sharing() connections_dict[id(conn)] = conn try: num_new_threads = 2 for x in range(num_new_threads): t = threading.Thread(target=runner) t.start() t.join() self.assertEqual( len(connections_dict), len(connections.all()) * (num_new_threads + 1), ) finally: # Finish by closing the connections opened by the other threads # (the connection opened in the main thread will automatically be # closed on teardown). for conn in connections_dict.values(): if conn is not connection: if conn.allow_thread_sharing: conn.close() conn.dec_thread_sharing() def test_pass_connection_between_threads(self): """ A connection can be passed from one thread to the other (#17258). """ Person.objects.create(first_name="John", last_name="Doe") def do_thread(): def runner(main_thread_connection): from django.db import connections connections['default'] = main_thread_connection try: Person.objects.get(first_name="John", last_name="Doe") except Exception as e: exceptions.append(e) t = threading.Thread(target=runner, args=[connections['default']]) t.start() t.join() # Without touching thread sharing, which should be False by default. exceptions = [] do_thread() # Forbidden! self.assertIsInstance(exceptions[0], DatabaseError) connections['default'].close() # After calling inc_thread_sharing() on the connection. connections['default'].inc_thread_sharing() try: exceptions = [] do_thread() # All good self.assertEqual(exceptions, []) finally: connections['default'].dec_thread_sharing() def test_closing_non_shared_connections(self): """ A connection that is not explicitly shareable cannot be closed by another thread (#17258). """ # First, without explicitly enabling the connection for sharing. exceptions = set() def runner1(): def runner2(other_thread_connection): try: other_thread_connection.close() except DatabaseError as e: exceptions.add(e) t2 = threading.Thread(target=runner2, args=[connections['default']]) t2.start() t2.join() t1 = threading.Thread(target=runner1) t1.start() t1.join() # The exception was raised self.assertEqual(len(exceptions), 1) # Then, with explicitly enabling the connection for sharing. exceptions = set() def runner1(): def runner2(other_thread_connection): try: other_thread_connection.close() except DatabaseError as e: exceptions.add(e) # Enable thread sharing connections['default'].inc_thread_sharing() try: t2 = threading.Thread(target=runner2, args=[connections['default']]) t2.start() t2.join() finally: connections['default'].dec_thread_sharing() t1 = threading.Thread(target=runner1) t1.start() t1.join() # No exception was raised self.assertEqual(len(exceptions), 0) def test_thread_sharing_count(self): self.assertIs(connection.allow_thread_sharing, False) connection.inc_thread_sharing() self.assertIs(connection.allow_thread_sharing, True) connection.inc_thread_sharing() self.assertIs(connection.allow_thread_sharing, True) connection.dec_thread_sharing() self.assertIs(connection.allow_thread_sharing, True) connection.dec_thread_sharing() self.assertIs(connection.allow_thread_sharing, False) msg = 'Cannot decrement the thread sharing count below zero.' with self.assertRaisesMessage(RuntimeError, msg): connection.dec_thread_sharing() class MySQLPKZeroTests(TestCase): """ Zero as id for AutoField should raise exception in MySQL, because MySQL does not allow zero for autoincrement primary key. """ @skipIfDBFeature('allows_auto_pk_0') def test_zero_as_autoval(self): with self.assertRaises(ValueError): Square.objects.create(id=0, root=0, square=1) class DBConstraintTestCase(TestCase): def test_can_reference_existent(self): obj = Object.objects.create() ref = ObjectReference.objects.create(obj=obj) self.assertEqual(ref.obj, obj) ref = ObjectReference.objects.get(obj=obj) self.assertEqual(ref.obj, obj) def test_can_reference_non_existent(self): self.assertFalse(Object.objects.filter(id=12345).exists()) ref = ObjectReference.objects.create(obj_id=12345) ref_new = ObjectReference.objects.get(obj_id=12345) self.assertEqual(ref, ref_new) with self.assertRaises(Object.DoesNotExist): ref.obj def test_many_to_many(self): obj = Object.objects.create() obj.related_objects.create() self.assertEqual(Object.objects.count(), 2) self.assertEqual(obj.related_objects.count(), 1) intermediary_model = Object._meta.get_field("related_objects").remote_field.through intermediary_model.objects.create(from_object_id=obj.id, to_object_id=12345) self.assertEqual(obj.related_objects.count(), 1) self.assertEqual(intermediary_model.objects.count(), 2)