dockerfixtures 0.0.0

Cointainers as Pytest fixture made easy

This package was inspired by others, but was written from scratch. But after trying to make heads and tails of them when faced with bugs, I ended-up finding simpler to start over.

Using dockerfixtures with pytest

To spawn a container in your tests, proceed as follow:

from dockerfixtures import image, container
import pytest


@pytest.fixture(scope='session')
def pg_image() -> image.Image:
    return image.Image('postgres', tags='12')

@pytest.fixture(scope='function')
def pg_container(pg_image: image.Image) -> container.Container:
    yield from container.fixture(some_image)

# If you don't need to reuse the image

@pytest.fixture(scope='session')
def pg_container() -> container.Container:
    some_image = image.Image('postgres', tags='12')
    yield from container.fixture(some_image)

Why not a pytest plugin ?

Other implementation of this have been provinding a pytest plugin, so you might wonder why this one doesn’t ?

First reason is I have not looked into it that much, yet.

But anyhow, you would still need to import the dockerfixtures.image module. So I am not very sure what the benefits would be ?

Also I found those plugins to provide somewhat bizarre API, for example to define the fixtures’ scope. I haven’t looked into why they do that, yet. Here there are no surprises, a container fixture looks like any other fixture.

Pytest plugins are global: they have to be imported in your top-level conftest.py (see note). I think it is good practice to keep your tests properly partitioned based on their external dependencies. It can help split workload if the need arises. In a collaborative environment, having to import dockerfixtures, may help prevent breaking that partitioning during reviews.