LESSON2.md

Lesson 2: Add a test to an existing role

• home

• back

• next

• add linting to the default test

• add a testinfra test to check if docker compose gets installed

• initialize a new scenario and write a test to check if docker compose doesn't get insalled when the flag is set to false

Initialize

Copy the folder lesson2_geerlingguy.docker into a new one and cd into it.

edit the existing scenario

Place the .yamllint you created in lesson 1 in the default directory.

edit the molecule/default/molecule.yml

---
dependency:
  name: galaxy
driver:
  name: docker
lint: |
  set -e
  yamllint .
  ansible-lint .
  flake8
platforms:
  - name: instance
    image: "geerlingguy/docker-ubuntu1804-ansible:latest"
    command: ${MOLECULE_DOCKER_COMMAND:-""}
    volumes:
      - /sys/fs/cgroup:/sys/fs/cgroup:ro
    privileged: true
    pre_build_image: true
provisioner:
  name: ansible
scenario:
  name: default
verifier:
  name: testinfra

It adds lintng and testinfra test.

Now create a tests directory in molecule/default and add a file test_default.py with content

import os

import testinfra.utils.ansible_runner

testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
    os.environ['MOLECULE_INVENTORY_FILE']).get_hosts('all')


def test_docker_compose_working(host):
    cmd = host.run('docker-compose --version')

    assert cmd.rc == 0


def test_for_docker_engine(host):
    cmd = host.run('docker info')

    assert cmd.rc == 0
    assert cmd.stdout.find("Running: 0") != -1

Run the test 1

docker run \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v $(pwd):$(pwd) -w $(pwd) \
  --user root \
  quay.io/ansible/molecule:3.0.2 \
  /bin/sh -c "pip3 install testinfra; molecule test --all"

Initialize a new scenario

docker run \
  -v $(pwd):$(pwd) -w $(pwd) \
  --user root \
  quay.io/ansible/molecule:3.0.2 \
  /bin/sh -c "molecule init scenario --verifier-name testinfra install_docker_without_docker_compose"

Now edit the molecule/install_docker_without_docker_compose/molecule.yml like this.

---
dependency:
  name: galaxy
driver:
  name: docker
lint: |
  set -e
  yamllint .
  ansible-lint .
  flake8
platforms:
  - name: instance
    image: "geerlingguy/docker-ubuntu1804-ansible:latest"
    command: ${MOLECULE_DOCKER_COMMAND:-""}
    volumes:
      - /sys/fs/cgroup:/sys/fs/cgroup:ro
    privileged: true
    pre_build_image: true
provisioner:
  name: ansible
verifier:
  name: testinfra

Write the test

To deactivate the docker compose installation you have to edit the playbook molecule/install_docker_without_docker_compose/converge.yml

---
- name: Converge
  hosts: all
  pre_tasks:
    - name: Update apt cache.
      apt: update_cache=yes cache_valid_time=600
      when: ansible_os_family == 'Debian'
  tasks:
    - name: "Include geerlingguy.docker"
      include_role:
        name: "geerlingguy.docker"
      vars:
        docker_install_compose: false

Then add a python test molecule/install_docker_without_dokcer_compose/tests/tests_default.py

import os

import testinfra.utils.ansible_runner

testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
    os.environ['MOLECULE_INVENTORY_FILE']).get_hosts('all')


def test_docker_compose_working(host):
    cmd = host.run('docker-compose --version')

    assert cmd.rc != 0

One adjustment to the generated code

The molecule/install_docker_without_dokcer_compose/tests/configtest.py line 19 is to long. Just edit this file to look like this.

"""PyTest Fixtures."""
from __future__ import absolute_import
import os
import pytest


def pytest_runtest_setup(item):
    """Run tests only when under molecule with testinfra installed."""
    try:
        import testinfra
    except ImportError:
        pytest.skip("Test requires testinfra", allow_module_level=True)
    if "MOLECULE_INVENTORY_FILE" in os.environ:
        pytest.testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
            os.environ["MOLECULE_INVENTORY_FILE"]
        ).get_hosts("all")
    else:
        pytest.skip(
            "Test should run only from inside molecule.",
            allow_module_level=True
        )

In real world scenarios, you can discuss these linting rules. Just make sure to not waste time with meaningless disussions.

Run the test 2

docker run \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v $(pwd):$(pwd) -w $(pwd) \
  --user root \
  quay.io/ansible/molecule:3.0.2 \
  /bin/sh -c "pip3 install testinfra; molecule test --all"