A (or maybe the) primary usecase for this package is is in writing test tests concisely, ergonmically, and readably.

To that end, we integrate with the testing framework in order to provide good UX in your tests.


We provide default implementations of a couple of pytest fixtures: mf_engine, mf_session, and mf_config. However this assumes you’re okay running your code as though it’s executed in SQLite, and with default session parameters.

If your system will work under those conditions, great! Simply go on and use the mf fixture which gives you a handle on a ModelFactory

from sqlalchemy_model_factory import registry

def new_foo():
    return Foo()

def test_foo(mf):
    foo = mf.foo.new()
    assert isinstance(foo, Foo)

If, however, you make use of feature not available in SQLite, you may need a handle on a real database engine. Supposing you’ve got a postgres database available at db:5432, you can put the following into your tests/conftest.py.

import pytest
from sqlalchemy import create_engine

def mf_engine():
    return create_engine('psycopg2+postgresql://db:5432')

# now the `mf` fixture should work

Furthermore, if your application works in a context where you assume your session has particular options set, you can similarly plug in your own session.

import pytest
from sqlalchemy.orm.session import sessionmaker

def mf_session(mf_engine):
    Session = sessionmaker()  # Set your options
    return Session(bind=engine)

# now the `mf` fixture should work

Finally, there are a set of hooks through which you can configure the behavior of the ModelFactory itself through the mf_config fixture. If defined, this fixture should return a dict, the contents of which would be the config options available.

Below is defined, the equivalent of a maximally defined mf_config fixture with all the values set to their defaults. Note That as a user, you only need to include options which you want overridden from their defaults.

def mf_config():
    return {
        # Whether the calling of all factory functions should commit, or just flush.
        "commit": True,

        # Whether the actions performed by the model-factory should attempt to revert. Certain
        # test circumstances (like complex relationships, or direct sql `execute` calls might
        # mean cleanup will fail an otherwise valid test.
        "cleanup": True,