Testing roles

Testing roles with molecule

Launch make execute_molecule to test all collections roles.

Roles can be tested individually using the molecule-venv created by running make execute_molecule. The molecule-venv can also be created manually.

% python3 -m venv molecule-venv
% source molecule-venv/bin/activate
(molecule-venv) % pip install --upgrade pip
(molecule-venv) % pip install -r molecule-requirements.txt

Afterwards the molecule-venv can be used to test a specific role. Note however that not all roles can be tested in a container, some may require a full-fledged VM. To make sure your role can be tested in a container, check the driver section in the molecule.yml file.

(molecule-venv) % cd roles/edpm_<role>
(molecule-venv) % molecule test # tests default scenario
(molecule-venv) % molecule test --all
(molecule-venv) % molecule test --scenario-name <specific scenario>

The edpm_timezone role molecule directory is a working example to borrow from when configuring the molecule directory for a new role. Copying the default molecule.yml file from edpm_timezone should be sufficient for the molecule test command to work.

Alternatively you can test roles in with AnsibleEE.

Creating a VM to run molecule

The edpm_libvirt molecule senario uses the delegated driver to run against localhost. Thus, it’s better to run it inside an ephemeral virtual machine as it cannot be run insider of a container.

Boot a VM based on CentOS-Stream-GenericCloud-9-latest.x86_64.qcow2 from https://cloud.centos.org/centos/9-stream/x86_64/images.

Use repo-setup to configure the DNF repositories of the VM.

pushd /tmp
curl -sL https://github.com/openstack-k8s-operators/repo-setup/archive/refs/heads/main.tar.gz | tar -xz
pushd repo-setup-main
python3 -m venv ./venv
PBR_VERSION=0.0.0 ./venv/bin/pip install ./
sudo ./venv/bin/repo-setup current-podified
popd
popd

Clone the git repository on the VM.

cd ~
sudo dnf install -y git
git clone git@github.com:openstack-k8s-operators/edpm-ansible.git

Prepare molecule.

pushd ~/edpm-ansible
python3 -m venv molecule-venv
source molecule-venv/bin/activate
pip install --upgrade pip
pip install bindep
bindep -b | xargs sudo dnf -y --setopt=install_weak_deps=False install
pip install -r molecule-requirements.txt
popd

Consider taking a snapshot of the VM before running a test like the following.

cd ~/edpm-ansible/roles/edpm_libvirt/
molecule test --all

Writing molecule tests

Molecule scenario configutration is made up of several files, all stored in the molecule/<scenario>/ directory.

• molecule/default/molecule.yml (mandatory):

  Main configuration file for molecule test, where the driver, platforms, images, provisioner, verifier etc. are specified. The most important part of the molecule.yml file is the scenario section where the test_sequence is being specified. E.g.:

  test_sequence:
  - dependency
  - destroy
  - create
  - prepare
  - converge
  - destroy
  

• molecule/default/converge.yml (mandatory):

  Corresponding to the converge step. Molecule will run this playbook to apply the role to the test instance(s).

• molecule/default/prepare.yml:

  Corresponding to the prepare step. It is used to perform any setup tasks that need to be done before your role can be applied.

• molecule/default/verify.yml:

  Corresponding to the verify step. This playbook is run to verify that the role did what was expected it to do.

The create, destroy, dependency, side_effect steps and other configuration are handled internally by Molecule and do not require separate playbook files. For instance, when Molecule executes the destroy step, it uses its internal logic, and any configuration specified in molecule.yml, to destroy the test instances.

However they can be customized further based on the specific needs of the role.