class Test_schema_upgrader(object):
def setUp(self):
# make an in-memory sqlite database to use during testing
self.connection = Connection_wrapper(
sqlite.connect(":memory:",
detect_types=sqlite.PARSE_DECLTYPES,
check_same_thread=False))
self.cache = Stub_cache()
cursor = self.connection.cursor()
cursor.execute(Stub_object.sql_create_table())
self.fake_files = {
} # map of fake filename (full path) to fake file contents
self.database = Database(self.connection, self.cache)
self.upgrader = Schema_upgrader(self.database,
glob=self.glob,
read_file=self.read_file)
def tearDown(self):
self.database.close()
def glob(self, glob_pattern):
"""
A fake glob function that doesn't use the filesystem.
"""
re_pattern = re.compile(glob_pattern.replace("*", "[^/]*"))
return [
filename for filename in self.fake_files.keys()
if re_pattern.search(filename)
]
def read_file(self, filename):
"""
A fake read file function that doesn't use the filesystem.
"""
contents = self.fake_files.get(filename)
if not contents:
raise IOError()
return contents
def test_upgrade_schema(self, to_version=None):
if not to_version:
to_version = u"5.7.11"
self.fake_files = {
u"model/delta/5.6.7.sqlite":
u"create table new_table ( foo text ); insert into new_table values ( 'hi' );",
u"model/delta/5.6.8.sqlite":
u"insert into new_table values ( 'bye' );",
u"model/delta/5.6.10.sqlite":
u"alter table new_table add column bar text;",
u"model/delta/5.7.11.sqlite":
u"insert into new_table values ( 'whee', 'stuff' );",
u"model/delta/5.7.18.sqlite":
u"insert into new_table values ( 'more', 'things' );",
}
self.upgrader.upgrade_schema(to_version)
result = self.database.select_many(tuple, u"select * from new_table;")
if to_version == u"5.7.11":
assert result == [(u"hi", None), (u"bye", None), ("whee", "stuff")]
else:
assert result == [(u"hi", None), (u"bye", None), ("whee", "stuff"),
("more", "things")]
result = self.database.select_many(tuple,
u"select * from schema_version;")
if to_version == u"5.7.11":
assert result == [(5, 7, 11)]
else:
assert result == [(5, 7, 18)]
def test_upgrade_schema_with_schema_version_table(self):
self.database.execute(
u"create table schema_version ( major numeric, minor numeric, \"release\" numeric );"
)
self.database.execute(
u"insert into schema_version values ( 0, 0, 0 );")
self.test_upgrade_schema()
def test_upgrade_schema_with_schema_version_table_and_starting_version(
self):
self.database.execute(
u"create table schema_version ( major numeric, minor numeric, \"release\" numeric );"
)
self.database.execute(
u"insert into schema_version values ( 5, 6, 6 );")
self.fake_files[
u"model/delta/5.6.1.sqlite"] = u"this is not valid sql and should not be executed anyway;"
self.fake_files[u"model/delta/5.6.6.sqlite"] = u"also invalid;"
self.test_upgrade_schema()
def test_upgrade_schema_with_schema_version_table_and_target_version_without_schema(
self):
self.database.execute(
u"create table schema_version ( major numeric, minor numeric, \"release\" numeric );"
)
self.database.execute(
u"insert into schema_version values ( 0, 0, 0 );")
self.test_upgrade_schema(to_version=u"5.7.20")
def test_upgrade_schema_with_schema_version_table_and_starting_version_and_target_version_without_schema(
self):
self.database.execute(
u"create table schema_version ( major numeric, minor numeric, \"release\" numeric );"
)
self.database.execute(
u"insert into schema_version values ( 5, 6, 6 );")
self.test_upgrade_schema(to_version=u"5.7.20")
def test_upgrade_schema_with_future_ending_version(self):
self.fake_files = {
u"model/delta/5.6.7.sqlite":
u"create table new_table ( foo text ); insert into new_table values ( 'hi' );",
u"model/delta/5.6.8.sqlite":
u"insert into new_table values ( 'bye' );",
u"model/delta/5.6.10.sqlite":
u"alter table new_table add column bar text;",
u"model/delta/5.7.11.sqlite":
u"insert into new_table values ( 'whee', 'stuff' );",
u"model/delta/5.7.18.sqlite":
u"insert into new_table values ( 'more', 'and more' );",
}
self.upgrader.upgrade_schema(u"5.8.55")
result = self.database.select_many(tuple, u"select * from new_table;")
assert result == [(u"hi", None), (u"bye", None), ("whee", "stuff"),
("more", "and more")]
result = self.database.select_many(tuple,
u"select * from schema_version;")
assert result == [(5, 7, 18)]
def test_upgrade_schema_twice(self):
self.test_upgrade_schema()
# the second upgrade should have no effect, because at this point it's already upgraded
self.test_upgrade_schema()
def test_upgrade_schema_with_filename_with_invalid_version(self):
# the filename, not composed of all-integer parts, should be skipped
self.fake_files[
u"model/delta/5.6.9b.sqlite"] = u"this is not valid sql and should not be executed anyway;"
self.test_upgrade_schema()
def test_upgrade_schema_default_to_start_version_of_1_5_4(self):
# test that if no schema_version table exists, then the starting version is assumed to be 1.5.4
self.fake_files = {
u"model/delta/1.5.3.sqlite":
u"invalid sql;",
u"model/delta/1.5.4.sqlite":
u"should not be invoked;",
u"model/delta/1.5.5.sqlite":
u"create table new_table ( foo text ); insert into new_table values ( 'hi' );",
u"model/delta/1.5.6.sqlite":
u"insert into new_table values ( 'bye' );",
}
self.upgrader.upgrade_schema(u"1.5.6")
result = self.database.select_many(tuple, u"select * from new_table;")
assert result == [
(u"hi", ),
(u"bye", ),
]
result = self.database.select_many(tuple,
u"select * from schema_version;")
assert result == [(1, 5, 6)]
def test_apply_schema_delta(self):
self.database.execute(
u"create table schema_version ( major numeric, minor numeric, \"release\" numeric );"
)
self.database.execute(
u"insert into schema_version values ( 0, 0, 0 );")
self.fake_files = {
u"model/delta/5.6.5.sqlite":
u"insert into new_table values ( 'should not show up' );",
u"model/delta/5.6.7.sqlite":
u"create table new_table ( foo text ); insert into new_table values ( 'hi' );",
u"model/delta/5.7.18.sqlite":
u"insert into new_table values ( 'should not be present' );",
}
self.upgrader.apply_schema_delta((5, 6, 7),
u"model/delta/5.6.7.sqlite")
result = self.database.select_many(unicode,
u"select * from new_table;")
assert result == [u"hi"]
result = self.database.select_many(tuple,
u"select * from schema_version;")
assert result == [(5, 6, 7)]
@raises(IOError)
def test_apply_schema_delta_with_unknown_file(self):
self.upgrader.apply_schema_delta((5, 6, 7),
u"model/delta/5.6.7.sqlite")
def test_version_string_to_tuple(self):
version = self.upgrader.version_string_to_tuple("2.5.13")
assert len(version) == 3
assert version[0] == 2
assert version[1] == 5
assert version[2] == 13
def test_version_string_to_tuple_with_extension(self):
version = self.upgrader.version_string_to_tuple("2.5.13.sqlite")
assert len(version) == 3
assert version[0] == 2
assert version[1] == 5
assert version[2] == 13
@raises(ValueError)
def test_version_string_to_tuple_with_too_many_parts(self):
version = self.upgrader.version_string_to_tuple("3.14.159.26.5")
@raises(ValueError)
def test_version_string_to_tuple_with_too_few_parts(self):
version = self.upgrader.version_string_to_tuple("3.14")
@raises(ValueError)
def test_version_string_to_tuple_with_non_integer_part(self):
version = self.upgrader.version_string_to_tuple("2.5b.13")
@raises(ValueError)
def test_version_string_to_tuple_with_empty_part(self):
version = self.upgrader.version_string_to_tuple("2..13")
class Test_database( object ):
def setUp( self ):
# make an in-memory sqlite database to use during testing
self.connection = Connection_wrapper( sqlite.connect( ":memory:", detect_types = sqlite.PARSE_DECLTYPES, check_same_thread = False ) )
self.cache = Stub_cache()
cursor = self.connection.cursor()
cursor.execute( Stub_object.sql_create_table() )
self.database = Database( self.connection, self.cache )
def tearDown( self ):
self.database.close()
def test_save_and_load( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.save( basic_obj )
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace( tzinfo = utc ) == original_revision
assert obj.value == basic_obj.value
def test_save_and_load_without_commit( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.save( basic_obj, commit = False )
self.connection.rollback() # if commit wasn't called, this should back out the save
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj == None
def test_save_and_load_with_explicit_commit( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.save( basic_obj, commit = False )
self.database.commit()
self.connection.rollback() # should have no effect because of the call to commit
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace( tzinfo = utc ) == original_revision
assert obj.value == basic_obj.value
def test_select_one( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.save( basic_obj )
obj = self.database.select_one( Stub_object, Stub_object.sql_load( basic_obj.object_id ) )
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace( tzinfo = utc ) == original_revision
assert obj.value == basic_obj.value
def test_select_datetime( self ):
# this revision (with .504099) happens to test for a bug caused by floating point rounding errors
original_revision = "2008-01-01 01:00:42.504099+00:00"
basic_obj = Stub_object( object_id = "5", revision = original_revision, value = 1 )
self.database.save( basic_obj )
obj = self.database.select_one( Stub_object, Stub_object.sql_load( basic_obj.object_id ) )
assert obj.object_id == basic_obj.object_id
assert str( obj.revision.replace( tzinfo = utc ) ) == original_revision
assert obj.value == basic_obj.value
def test_select_datetime_with_many_fractional_digits( self ):
original_revision = "2008-01-01 01:00:42.5032429489284+00:00"
basic_obj = Stub_object( object_id = "5", revision = original_revision, value = 1 )
self.database.save( basic_obj )
obj = self.database.select_one( Stub_object, Stub_object.sql_load( basic_obj.object_id ) )
assert obj.object_id == basic_obj.object_id
assert str( obj.revision.replace( tzinfo = utc ) ) == "2008-01-01 01:00:42.503242+00:00"
assert obj.value == basic_obj.value
def test_select_datetime_with_zero_fractional_seconds( self ):
original_revision = "2008-01-01 01:00:42.0+00:00"
basic_obj = Stub_object( object_id = "5", revision = original_revision, value = 1 )
self.database.save( basic_obj )
obj = self.database.select_one( Stub_object, Stub_object.sql_load( basic_obj.object_id ) )
assert obj.object_id == basic_obj.object_id
assert str( obj.revision.replace( tzinfo = utc ) ) == "2008-01-01 01:00:42+00:00"
assert obj.value == basic_obj.value
def test_select_one_tuple( self ):
obj = self.database.select_one( tuple, Stub_object.sql_tuple() )
assert len( obj ) == 2
assert obj[ 0 ] == 1
assert obj[ 1 ] == 2
def test_select_many( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
basic_obj2 = Stub_object( object_id = "6", value = 2 )
original_revision2 = basic_obj2.revision
self.database.save( basic_obj )
self.database.save( basic_obj2 )
objs = self.database.select_many( Stub_object, Stub_object.sql_load_em_all() )
assert len( objs ) == 2
assert objs[ 0 ].object_id == basic_obj.object_id
assert objs[ 0 ].revision.replace( tzinfo = utc ) == original_revision
assert objs[ 0 ].value == basic_obj.value
assert objs[ 1 ].object_id == basic_obj2.object_id
assert objs[ 1 ].revision.replace( tzinfo = utc ) == original_revision2
assert objs[ 1 ].value == basic_obj2.value
def test_select_many_tuples( self ):
objs = self.database.select_many( tuple, Stub_object.sql_tuple() )
assert len( objs ) == 1
assert len( objs[ 0 ] ) == 2
assert objs[ 0 ][ 0 ] == 1
assert objs[ 0 ][ 1 ] == 2
def test_select_many_with_no_matches( self ):
objs = self.database.select_many( Stub_object, Stub_object.sql_load_em_all() )
assert len( objs ) == 0
def test_save_and_load_revision( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.save( basic_obj )
basic_obj.value = 2
self.database.save( basic_obj )
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace( tzinfo = utc ) == basic_obj.revision
assert obj.value == basic_obj.value
revised = self.database.load( Stub_object, basic_obj.object_id, revision = original_revision )
assert revised.object_id == basic_obj.object_id
assert revised.value == 1
assert revised.revision.replace( tzinfo = utc ) == original_revision
def test_execute( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.execute( basic_obj.sql_create() )
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace( tzinfo = utc ) == original_revision
assert obj.value == basic_obj.value
def test_execute_without_commit( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.execute( basic_obj.sql_create(), commit = False )
self.connection.rollback()
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj == None
def test_execute_with_explicit_commit( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
original_revision = basic_obj.revision
self.database.execute( basic_obj.sql_create(), commit = False )
self.database.commit()
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace( tzinfo = utc ) == original_revision
assert obj.value == basic_obj.value
def test_load_unknown( self ):
basic_obj = Stub_object( object_id = "5", value = 1 )
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj == None
def test_next_id( self ):
next_id = self.database.next_id( Stub_object )
assert next_id
assert self.database.load( Stub_object, next_id )
prev_ids = [ next_id ]
next_id = self.database.next_id( Stub_object )
assert next_id
assert next_id not in prev_ids
assert self.database.load( Stub_object, next_id )
prev_ids.append( next_id )
next_id = self.database.next_id( Stub_object )
assert next_id
assert next_id not in prev_ids
assert self.database.load( Stub_object, next_id )
def test_next_id_without_commit( self ):
next_id = self.database.next_id( Stub_object, commit = False )
self.connection.rollback()
assert self.database.load( Stub_object, next_id ) == None
def test_next_id_with_explicit_commit( self ):
next_id = self.database.next_id( Stub_object, commit = False )
self.database.commit()
assert next_id
assert self.database.load( Stub_object, next_id )
def test_synchronize( self ):
def make_objects():
for i in range( 50 ):
object_id = self.database.next_id( Stub_object )
basic_obj = Stub_object( object_id, value = 1 )
original_revision = basic_obj.revision
self.database.execute( basic_obj.sql_create() )
obj = self.database.load( Stub_object, basic_obj.object_id )
assert obj.object_id == basic_obj.object_id
delta = abs( obj.revision.replace( tzinfo = utc ) - original_revision )
assert delta <= timedelta( seconds = 0.000001 )
assert obj.value == basic_obj.value
object_id = self.database.next_id( Stub_object )
# if synchronization (locking) is working properly, then these two threads should be able to run
# simultaneously without error. without locking, SQLite will raise
thread1 = Thread( target = make_objects )
thread2 = Thread( target = make_objects )
thread1.start()
thread2.start()
thread1.join()
thread2.join()
def test_backend( self ):
assert self.database.backend == Persistent.SQLITE_BACKEND
class Test_database(object):
def setUp(self):
# make an in-memory sqlite database to use during testing
self.connection = Connection_wrapper(
sqlite.connect(":memory:",
detect_types=sqlite.PARSE_DECLTYPES,
check_same_thread=False))
self.cache = Stub_cache()
cursor = self.connection.cursor()
cursor.execute(Stub_object.sql_create_table())
self.database = Database(self.connection, self.cache)
def tearDown(self):
self.database.close()
def test_save_and_load(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.save(basic_obj)
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace(tzinfo=utc) == original_revision
assert obj.value == basic_obj.value
def test_save_and_load_without_commit(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.save(basic_obj, commit=False)
self.connection.rollback(
) # if commit wasn't called, this should back out the save
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj == None
def test_save_and_load_with_explicit_commit(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.save(basic_obj, commit=False)
self.database.commit()
self.connection.rollback(
) # should have no effect because of the call to commit
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace(tzinfo=utc) == original_revision
assert obj.value == basic_obj.value
def test_select_one(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.save(basic_obj)
obj = self.database.select_one(
Stub_object, Stub_object.sql_load(basic_obj.object_id))
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace(tzinfo=utc) == original_revision
assert obj.value == basic_obj.value
def test_select_datetime(self):
# this revision (with .504099) happens to test for a bug caused by floating point rounding errors
original_revision = "2008-01-01 01:00:42.504099+00:00"
basic_obj = Stub_object(object_id="5",
revision=original_revision,
value=1)
self.database.save(basic_obj)
obj = self.database.select_one(
Stub_object, Stub_object.sql_load(basic_obj.object_id))
assert obj.object_id == basic_obj.object_id
assert str(obj.revision.replace(tzinfo=utc)) == original_revision
assert obj.value == basic_obj.value
def test_select_datetime_with_many_fractional_digits(self):
original_revision = "2008-01-01 01:00:42.5032429489284+00:00"
basic_obj = Stub_object(object_id="5",
revision=original_revision,
value=1)
self.database.save(basic_obj)
obj = self.database.select_one(
Stub_object, Stub_object.sql_load(basic_obj.object_id))
assert obj.object_id == basic_obj.object_id
assert str(obj.revision.replace(
tzinfo=utc)) == "2008-01-01 01:00:42.503242+00:00"
assert obj.value == basic_obj.value
def test_select_datetime_with_zero_fractional_seconds(self):
original_revision = "2008-01-01 01:00:42.0+00:00"
basic_obj = Stub_object(object_id="5",
revision=original_revision,
value=1)
self.database.save(basic_obj)
obj = self.database.select_one(
Stub_object, Stub_object.sql_load(basic_obj.object_id))
assert obj.object_id == basic_obj.object_id
assert str(
obj.revision.replace(tzinfo=utc)) == "2008-01-01 01:00:42+00:00"
assert obj.value == basic_obj.value
def test_select_one_tuple(self):
obj = self.database.select_one(tuple, Stub_object.sql_tuple())
assert len(obj) == 2
assert obj[0] == 1
assert obj[1] == 2
def test_select_many(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
basic_obj2 = Stub_object(object_id="6", value=2)
original_revision2 = basic_obj2.revision
self.database.save(basic_obj)
self.database.save(basic_obj2)
objs = self.database.select_many(Stub_object,
Stub_object.sql_load_em_all())
assert len(objs) == 2
assert objs[0].object_id == basic_obj.object_id
assert objs[0].revision.replace(tzinfo=utc) == original_revision
assert objs[0].value == basic_obj.value
assert objs[1].object_id == basic_obj2.object_id
assert objs[1].revision.replace(tzinfo=utc) == original_revision2
assert objs[1].value == basic_obj2.value
def test_select_many_tuples(self):
objs = self.database.select_many(tuple, Stub_object.sql_tuple())
assert len(objs) == 1
assert len(objs[0]) == 2
assert objs[0][0] == 1
assert objs[0][1] == 2
def test_select_many_with_no_matches(self):
objs = self.database.select_many(Stub_object,
Stub_object.sql_load_em_all())
assert len(objs) == 0
def test_save_and_load_revision(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.save(basic_obj)
basic_obj.value = 2
self.database.save(basic_obj)
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace(tzinfo=utc) == basic_obj.revision
assert obj.value == basic_obj.value
revised = self.database.load(Stub_object,
basic_obj.object_id,
revision=original_revision)
assert revised.object_id == basic_obj.object_id
assert revised.value == 1
assert revised.revision.replace(tzinfo=utc) == original_revision
def test_execute(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.execute(basic_obj.sql_create())
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace(tzinfo=utc) == original_revision
assert obj.value == basic_obj.value
def test_execute_without_commit(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.execute(basic_obj.sql_create(), commit=False)
self.connection.rollback()
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj == None
def test_execute_with_explicit_commit(self):
basic_obj = Stub_object(object_id="5", value=1)
original_revision = basic_obj.revision
self.database.execute(basic_obj.sql_create(), commit=False)
self.database.commit()
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj.object_id == basic_obj.object_id
assert obj.revision.replace(tzinfo=utc) == original_revision
assert obj.value == basic_obj.value
def test_load_unknown(self):
basic_obj = Stub_object(object_id="5", value=1)
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj == None
def test_next_id(self):
next_id = self.database.next_id(Stub_object)
assert next_id
assert self.database.load(Stub_object, next_id)
prev_ids = [next_id]
next_id = self.database.next_id(Stub_object)
assert next_id
assert next_id not in prev_ids
assert self.database.load(Stub_object, next_id)
prev_ids.append(next_id)
next_id = self.database.next_id(Stub_object)
assert next_id
assert next_id not in prev_ids
assert self.database.load(Stub_object, next_id)
def test_next_id_without_commit(self):
next_id = self.database.next_id(Stub_object, commit=False)
self.connection.rollback()
assert self.database.load(Stub_object, next_id) == None
def test_next_id_with_explicit_commit(self):
next_id = self.database.next_id(Stub_object, commit=False)
self.database.commit()
assert next_id
assert self.database.load(Stub_object, next_id)
def test_synchronize(self):
def make_objects():
for i in range(50):
object_id = self.database.next_id(Stub_object)
basic_obj = Stub_object(object_id, value=1)
original_revision = basic_obj.revision
self.database.execute(basic_obj.sql_create())
obj = self.database.load(Stub_object, basic_obj.object_id)
assert obj.object_id == basic_obj.object_id
delta = abs(
obj.revision.replace(tzinfo=utc) - original_revision)
assert delta <= timedelta(seconds=0.000001)
assert obj.value == basic_obj.value
object_id = self.database.next_id(Stub_object)
# if synchronization (locking) is working properly, then these two threads should be able to run
# simultaneously without error. without locking, SQLite will raise
thread1 = Thread(target=make_objects)
thread2 = Thread(target=make_objects)
thread1.start()
thread2.start()
thread1.join()
thread2.join()
def test_backend(self):
assert self.database.backend == Persistent.SQLITE_BACKEND