Setting up pytest django database

Question

I need to run this SQL after the test database is created but before creating any tables:

`CREATE EXTENSION pg_trgm;
CREATE EXTENSION btree_gin;

I know that I can somehow use django_db_setup fixture to do this but I can't figure out how.
I use

addopts = --no-migrations

in my pytest.ini file so this can't be done using migrations

It should be something like this:

@pytest.fixture(scope='session')
def django_db_setup():
    # Some code to create database
        with connection.cursor() as cursor:
            cursor.execute('CREATE EXTENSION IF NOT EXISTS pg_trgm;')
            cursor.execute('CREATE EXTENSION IF NOT EXISTS btree_gin;')
    # Code for creating tables

Answer 1

@pytest.fixture(scope="session")
def django_migration_disabler() -> None:
    """Disable migrations when running django tests.

    This copies/alters the behavior of pytest_django.fixtures._disable_migrations,
    which is called when pytest is invoked with --no-migrations.

    See: https://github.com/pytest-dev/pytest-django/blob/v4.5.2/pytest_django/fixtures.py#L260

    We do this instead of invoking with --no-migrations because constructing the
    database without migrations fails to create necessary postgres extensions like
    citext and uuid-ossp.

    We then override the django_db_setup fixture and ensure that this
    fixture is called before the parent django_db_setup fixture.
    """
    from django.conf import settings
    from django.core.management.commands import migrate
    from django.db import connections

    class DisableMigrations:
        def __contains__(self, item: str) -> bool:
            return True

        def __getitem__(self, item: str) -> None:
            return None

    settings.MIGRATION_MODULES = DisableMigrations()

    class MigrateSilentCommand(migrate.Command):
        def handle(self, *args, **options):
            options["verbosity"] = 0
            database = options["database"]
            connection = connections[database]
            with connection.cursor() as cursor:
                cursor.execute('CREATE EXTENSION IF NOT EXISTS pg_trgm;')
                cursor.execute('CREATE EXTENSION IF NOT EXISTS btree_gin;')
            return super().handle(*args, **options)

    migrate.Command = MigrateSilentCommand  # type: ignore


@pytest.fixture(scope="session")
def django_db_use_migrations() -> bool:
    """Force pytest-django to use migrations.

    This is necessary because we disable migrations in the django_migration_disabler
    and the existing pytest-django mechanisms would override our disabling mechanism
    with their own, which would fail to create the necessary extensions in postgres.
    """
    return True


@pytest.fixture(scope="session")
def django_db_setup(django_migration_disabler, django_db_setup, django_db_blocker):
    """Override django_db_setup ensuring django_migration_disabler is loaded."""
    pass