Example of configuring a database with Alembic migrations using the 'pytest-async-sqlalchemy' lib

conftest_alembic.py

import asyncio

import pytest
from alembic.command import upgrade as alembic_upgrade
from alembic.config import Config as AlembicConfig
from pytest_async_sqlalchemy import create_database, drop_database


@pytest.fixture(scope="session")
def event_loop():
    """Create an instance of the default event loop for the test session."""
    loop = asyncio.new_event_loop()
    yield loop
    loop.close()


@pytest.fixture(scope="session")
def _database_url():
    """Return database url with driver."""
    return 'postgresql+asyncpg://user:1234@localhost/dbtest'


@pytest.fixture(scope="session")
async def database(database_url, event_loop):
    """Set up database with alembic migrations."""
    await create_database(database_url)

    alembic_config = AlembicConfig('alembic.ini')
    alembic_upgrade(alembic_config, 'head')

    try:
        yield database_url
    finally:
        await drop_database(database_url)

By the way, make sure your test database url for Alembic does not contain a driver and is configured correctly in env.py