Problem with docker-compose, django and mysql during testing

I am using docker-compose along with django and mysql, and I want in the custom entrypoint of django I want to do tests via python manage.py test. Since I am connected to mysql, by default it goes to look for the database test_NAMEDATABASE, but it doesn't find it. So I tried to create it as it says here, but I have several problems with permissions. I think this is a very common situation, how did you solve it? This is my mysql service in docker-compose.yml:

  db:
image: mysql:latest
command: --default-authentication-plugin=mysql_native_password
ports:
  - 3306:${MYSQL_DATABASE_PORT}
environment:
  - MYSQL_RANDOM_ROOT_PASSWORD
  - MYSQL_USER
  - MYSQL_PASSWORD
  - MYSQL_DATABASE
  - MYSQL_DATABASE_HOST
  - MYSQL_DATABASE_PORT
volumes:
  - mysql_data:/var/lib/mysql

And this is my settings.py settings in django:

    'default': {
    'ENGINE': 'django.db.backends.mysql', 
    'NAME': os.environ.get('MYSQL_DATABASE'),
    'USER': os.environ.get('MYSQL_USER'),
    'PASSWORD': os.environ.get('MYSQL_PASSWORD'),
    'HOST': os.environ.get('MYSQL_DATABASE_HOST'),   # Or an IP Address that your DB is hosted on
    'PORT': os.environ.get('MYSQL_DATABASE_PORT')
}

It gives me this error when I try to manually create the database "test_NAMEDATABASE" inside the mysql container: "Access denied for user 'django'@'%' to database 'test_NAMEDATABASE"

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