Docker-based integration tests

Description

Simple pytest fixtures that help you write integration tests with Docker and docker-compose. Specify all necessary containers in a docker-compose.yml file and and pytest-docker will spin them up for the duration of your tests.

This package is tested with Python versions 3.6, 3.7, 3.8 and 3.9, and pytest version 4, 5 and 6. Python 2 is not supported.

pytest-docker was originally created by André Caron.

Installation

Install pytest-docker with pip or add it to your test requirements. It is recommended to install docker-compose python package directly in your environment to ensure that it is available during tests. This will prevent potential dependency conflicts that can occur when the system wide docker-compose is used in tests.

The default behavior is not to install docker-compose with pytest-docker. If you want to, you install pytest-docker with the docker-compose-v1 extra. You can use the following command:

pip install pytest-docker[docker-compose-v1]

Docker Compose v2 compatiblity

pytest-docker will work with Docker Compose v2 out of the box if compose-switch is installed.

If you want to use the real Docker Compose v2, it has to be installed system wide (more information) and you have to modify the docker-compose-command fixture (this behavior might change in the future versions).

Usage

Here is an example of a test that depends on a HTTP service.

With a docker-compose.yml file like this (using the httpbin service):

version: '2'
services:
  httpbin:
    image: "kennethreitz/httpbin"
    ports:
      - "8000:80"

You can write a test like this:

import pytest
import requests

from requests.exceptions import ConnectionError


def is_responsive(url):
    try:
        response = requests.get(url)
        if response.status_code == 200:
            return True
    except ConnectionError:
        return False


@pytest.fixture(scope="session")
def http_service(docker_ip, docker_services):
    """Ensure that HTTP service is up and responsive."""

    # `port_for` takes a container port and returns the corresponding host port
    port = docker_services.port_for("httpbin", 80)
    url = "http://{}:{}".format(docker_ip, port)
    docker_services.wait_until_responsive(
        timeout=30.0, pause=0.1, check=lambda: is_responsive(url)
    )
    return url


def test_status_code(http_service):
    status = 418
    response = requests.get(http_service + "/status/{}".format(status))

    assert response.status_code == status

By default this plugin will try to open docker-compose.yml in your tests directory. If you need to use a custom location, override the docker_compose_file fixture inside your conftest.py file:

import os
import pytest


@pytest.fixture(scope="session")
def docker_compose_file(pytestconfig):
    return os.path.join(str(pytestconfig.rootdir), "mycustomdir", "docker-compose.yml")

Available fixtures

All fixtures have session scope.

docker_ip

Determine the IP address for TCP connections to Docker containers.

docker_compose_file

Get an absolute path to the docker-compose.yml file. Override this fixture in your tests if you need a custom location.

docker_compose_project_name

Generate a project name using the current process PID. Override this fixture in your tests if you need a particular project name.

docker_services

Start all services from the docker compose file (docker-compose up). After test are finished, shutdown all services (docker-compose down).

docker_compose_command

Docker Compose command to use to execute Dockers. Default is to use Docker Compose v1 (command is docker-compose). If you want to use Docker Compose v2, change this fixture to return docker compose.

docker_setup

Get the docker_compose command to be executed for test spawn actions. Override this fixture in your tests if you need to change spawn actions. Returning anything that would evaluate to False will skip this command.

docker_cleanup

Get the docker_compose command to be executed for test clean-up actions. Override this fixture in your tests if you need to change clean-up actions. Returning anything that would evaluate to False will skip this command.

Development

Use of a virtual environment is recommended. See the venv package for more information.

First, install pytest-docker and its test dependencies:

pip install -e ".[tests]"

Run tests with

pytest -c setup.cfg

to make sure that the correct configuration is used. This is also how tests are run in CI.

Use black with default settings for formatting. You can also use pylint with setup.cfg as the configuration file.

Contributing

This pytest plug-in and its source code are made available to you under a MIT license. It is safe to use in commercial and closed-source applications. Read the license for details!

Found a bug? Think a new feature would make this plug-in more practical? We welcome issues and pull requests!

When creating a pull request, be sure to follow this projects conventions (see above).