django_db_block access wrong database bug

when i tried this command pytest -s --import-mode=importlib it works fine.
but when i tried this pytest -s --import-mode=importlib app/tests/test_filename.py
first time was a general fail output but after that i got this error:

===================================================================================== ERRORS =====================================================================================
_________________________________________________________________ ERROR at setup of test_endpoint_containerList __________________________________________________________________
                                                                                                                                                                                  
self = <django.db.backends.utils.CursorWrapper object at 0x107070190>
sql = 'INSERT INTO "auth_user" ("password", "last_login", "is_superuser", "username", "first_name", "last_name", "email", "is_staff", "is_active", "date_joined") VALUES (%s, %s, 
%s, %s, %s, %s, %s, %s, %s, %s) RETURNING "auth_user"."id"'             
params = ('pbkdf2_sha256$180000$UlJQcZHRuts0$jpA8wYudq5I+QdAPXWe6lvqU7V4t3CvADtn4iXpfR64=', None, False, 'test', '', '', ...)
ignored_wrapper_args = (False, {'connection': <django.db.backends.postgresql.base.DatabaseWrapper object at 0x1068fd290>, 'cursor': <django.db.backends.utils.CursorWrapper object
 at 0x107070190>})                                                                                                                                                                
                                                                                         
    def _execute(self, sql, params, *ignored_wrapper_args):                                                                                                                       
        self.db.validate_no_broken_transaction()
        with self.db.wrap_database_errors:                                                                                                                                        
            if params is None:             
                # params default might be backend specific.                                                                                                                       
                return self.cursor.execute(sql)                
            else:                                                                                                                                                                 
>               return self.cursor.execute(sql, params)
E               psycopg2.errors.UniqueViolation: duplicate key value violates unique constraint "auth_user_username_key"
E               DETAIL:  Key (username)=(test) already exists.                                                                                                                                                                                                             
../../.pyenv/versions/3.7.4/envs/dsl/lib/python3.7/site-packages/django/db/backends/utils.py:86: UniqueViolation             
                                                                                                                                                                                  The above exception was the direct cause of the following exception:

django_db_blocker = <pytest_django.plugin._DatabaseBlocker object at 0x105377f90>
                                                                                         
    @pytest.fixture(scope='session')      
    def test_client(django_db_blocker):
        with django_db_blocker.unblock():                                                
>           User.objects.create_user('test', 'test@test.com', 'test123')
                                            
conftest.py:20:

i checked my postgres database test_dbname first and select auth_user this table and it was empty i couldn't find this user i saved. i found it insert to my original database dbname auth_user table. it only occurred when i test specific test file

my conftest.py

@pytest.fixture(scope='session')
def test_client(django_db_blocker):
    with django_db_blocker.unblock():
        User.objects.create_user('test', 'test@test.com', 'test123')
        client = APIClient()
        client.login(username='test', password='test123')

    return client

my project structure

│   conftest.py    
│
└───app_folder
│   │   apps.py
│   │   models.py
│   │   ...
│   └───tests
│       │   test_file1.py
│       │   test_file2.py

Start with conftest.py:20 and the session-scoped test_client fixture using django_db_blocker.unblock(). Reproduce with pytest -s --import-mode=importlib and then the app/tests/test_filename.py form, checking which database receives the auth_user insert. Done means the specific-file run uses the intended test database without the duplicate-user failure.