Plan:

• Find the unit tests in the repository (their could be multiple “tests/unit” folders).
• Ensure each set of unit tests is following the implementation standards.
• Run the tests to ensure the code work as expected.

Implementation standards

• Unit test should be implemented with ops.testing, not harness.

• Lint produced code with tox -e lint.

Testing

Writing unit tests

• Unit test must be implemented with ops.testing:

  • See How to migrate unit tests from Harness if the charm is currently using harness.

• For each charm in the repository, there should be a tests/ folder like: https://github.com/canonical/platform-engineering-charm-template/tree/main/tests

  • Unit tests goes in tests/unit
  • Fixtures should look like the ones in https://raw.githubusercontent.com/canonical/haproxy-operator/refs/heads/main/haproxy-operator/tests/unit/conftest.py
  • Helper functions should go in tests/unit/helper.py. See an example here: https://raw.githubusercontent.com/canonical/haproxy-operator/refs/heads/main/haproxy-operator/tests/unit/helper.py
  • There is a tests/unit/test_charm.py to test the basic behaviors of the charm.
  • There should be additional tests/unit/test_xxx.py files to test specific integrations of the charm (see https://github.com/canonical/haproxy-operator/tree/main/haproxy-operator/tests/unit)

Local testing

The unit tests should be run in a virtual machine named “charmkeeper”.

If the machine doesn’t exist, create it with: scripts/create-charmkeeper-vm.sh.

If not already done, mount the working directory folder in the machine with

multipass mount --type native $PWD charmkeeper:/workdir

Look at CONTRIBUTING.md to see if there are specific instructions to test the charm.

Unless there is something specific mentioned, you should be able to run the tests with:

multipass exec charmkeeper -d /workdir/ -- tox