Running django tests with selenium in docker

Here is how I do it. The basic problem is that docker-compose run will generate a different hostname (project_container_run_x) where x is hard to know for sure. I ended up just going off of ip address. I'm also ensuring DEBUG is False otherwise I get a bad request.

I'm using StaticLiveServerTestCase like this:

import osimport socketos.environ['DJANGO_LIVE_TEST_SERVER_ADDRESS'] = '0.0.0.0:8000'class IntegrationTests(StaticLiveServerTestCase):    live_server_url = 'http://{}:8000'.format(        socket.gethostbyname(socket.gethostname())    )    def setUp(self):        settings.DEBUG = True        self.browser = webdriver.Remote(            command_executor="http://selenium:4444/wd/hub",            desired_capabilities=DesiredCapabilities.CHROME        )    def tearDown(self):        self.browser.quit()        super().tearDown()    def test_home(self):        self.browser.get(self.live_server_url)

My docker-compose file has this for selenium and extends the web container (where django is running). Port 5900 is open for VNC. I like to keep this isolated in something like docker-compose.selenium.yml

version: '2'services:  web:    environment:      SELENIUM_HOST: http://selenium:4444/wd/hub      TEST_SELENIUM: 'yes'    depends_on:      - selenium  selenium:    image: selenium/standalone-chrome-debug    ports:      - "5900:5900"

I can run tests like

docker-compose run --rm web ./manage.py test

So my web container is accessing selenium via the "selenium" host. Selenium then accesses the web container by ip address which is determined on the fly.

Another gotcha is that it's tempting to just use "web" as the hostname. If your docker-compose run command starts up a separate web container - this will appear to work. However it won't be using your test database, making for not a great test.

For anyone running pytest, and possibly pytest-splinter (Selenium wrapper)

version: '3'services:  db:    image: postgres  django:    build: .    ports:       - "8000:8000"    depends_on:      - db      - selenium  selenium:    image: selenium/standalone-firefox-debug:latest    ports:      - "4444:4444"   # Selenium      - "5900:5900"   # VNC 

Define a conftest.py in your root directory to make these fixtures available to all your tests

import socketimport pytestfrom pytest_django.live_server_helper import LiveServer@pytest.fixture(scope='session')def test_server() -> LiveServer:    addr = socket.gethostbyname(socket.gethostname())    server = LiveServer(addr)    yield server    server.stop()@pytest.fixture(autouse=True, scope='function')def _test_server_helper(request):    """    Configures test_server fixture so you don't have to mark    tests with @pytest.mark.django_db    """    if "test_server" not in request.fixturenames:        return    request.getfixturevalue("transactional_db")# Settings below here are exclusive to splinter,# I'm just overriding the default browser fixture settings# If you just use selenium, no worries, just take note of the remote url and use # it wherever you define your selenium browser@pytest.fixture(scope='session')def splinter_webdriver():    return 'remote'@pytest.fixture(scope='session')def splinter_remote_url():    return 'http://selenium:4444/wd/hub'

Don't forget to set ALLOWED_HOSTS in your config file:

if env('USE_DOCKER') == 'yes':    import socket    ALLOWED_HOSTS = [socket.gethostbyname(socket.gethostname())]# or justALLOWED_HOSTS = ['*']

Then just test away!

from django.urls import reversedef test_site_loads(browser, test_server):    browser.visit(test_server.url + reverse('admin:index'))

I have just specified host='web' for LiveServerTestCase. Here is my working solution.

test.py

from django.test import LiveServerTestCasefrom selenium import webdriverfrom selenium.webdriver.common.desired_capabilities import DesiredCapabilitiesclass FunctionalTestCase(LiveServerTestCase):    host = 'web'    def setUp(self):        self.browser = webdriver.Remote(            command_executor="http://selenium:4444/wd/hub",            desired_capabilities=DesiredCapabilities.FIREFOX        )    def test_user_registration(self):        self.browser.get(self.live_server_url)        self.assertIn('Django', self.browser.title)    def tearDown(self):        self.browser.close()

docker-compose.yml

version: '3'services:  db:    image: postgres  web:    build: .    ports:       - "8000:8000"    depends_on:      - db      - selenium  selenium:    image: selenium/standalone-firefox

Remember you have to have to install the selenium in your docker image for this to work:

$ docker-compose exec web bash> pip install selenium...> pip freeze > ../requirements.txt> exit$ ...