How to use Module from pytest testinfra to validate running docker container

Question

All, i have been struggling with trying to use the modules example from https://testinfra.readthedocs.io/en/latest/examples.html#parametrize-your-tests. Test Docker images

Scenario: I have an image that is spun up through my CICD pipeline, and I want to use bind to that docker image and validate a few item in that container.

 # scope='session' uses the same container for all the tests;
# scope='function' uses a new container per test function.
@pytest.fixture(scope='session')
def host(request):
     #build local ./Dockerfile
     #
    # docker build -t <my.container.registry.io>/<my_app>:<my_tag> .
    #subprocess.check_call(['docker','build', '-f', 'gitlab.CHANGECOMPANYNAME:8443/mhs/SOMEURLNAME/cicd/platform-infrastructure/gitlab-tools/gitlab-runners/docker-in-docker:19.03.18', '.'])
    # run a container
    docker_id = subprocess.check_output(
        ['docker', 'run', '-d', 'gitlab.CHANGECOMPANYNAME.net:8443/mhs/SOMEURLNAE/cicd/platform-infrastructure/gitlab-tools/gitlab-runners/docker-in-docker:1.021']).decode().strip()
    # return a testinfra connection to the containe
    
    yield testinfra.get_host("docker://" + docker_id)
    print("printing  dockerid" + docker_id)
 # scope='function' uses a new container per test function.

So i know i am connected to the container khemlall we are tsting out the host now E printing dockerid18c53af26148f9cabe8d3 (change it here)

Now what i want is to use the module available to pytest from testinfra.. https://testinfra.readthedocs.io/en/latest/modules.html#testinfra.modules.file.File
Example

File class File(path) Test various files attributes within that container but can't seem to get this working or have any intellisense to select that i am accessing the module.

i Want to test to see if say python version 3.7 is installed or something like that...but can't seem to get this to work... any ideas..

def test_python_3_7(host):
"""
Check the Python 3.7 is used when running the Python command
"""
python_version = host.command('python --version').stdout
#assert host.('3.7', python_version)

Answer 1

I was able to get this working by adding 'sleep' as an entrypoint, I believe your issue is that the container stopped running (due to the entrypoint process completing) before testinfra could run commands. I also added a teardown step so you don't spawn a bunch of containers as you're testing.

import os

import pytest
import testinfra
import subprocess

@pytest.fixture(scope='session')
def host(request):
    subprocess.check_call(['docker','build', '-t', 'testcontainer', '.'])   
    docker_id = subprocess.check_output(['docker', 'run','-d', '--entrypoint', 'sleep', 'testcontainer','infinity']).decode().strip()
    yield testinfra.get_host("docker://" + docker_id)

    # teardown post
    print("attempting to kill: " + docker_id)
    subprocess.call(['docker','kill',docker_id])

def test_python_3_10(host):
    python_version = host.command('python3 --version').stdout.strip()
    assert python_version == "Python 3.10.6"