jjx is a very experimental test adapter for Kubernetes charms. It provides a juju command that can "deploy" unpacked charms:

• The charm source runs locally, inside a lightweight sandbox
• The workload runs as a Docker container

There's no cloud or controller, but from the charm's perspective everything is real. Pebble is really managing the container. The expected hook tools are available.

jjx's juju command is intended to be a drop-in replacement for charm integration tests. The juju CLI has just enough Juju-compatible functionality that Jubilant thinks it's talking to the real thing.

Fast integration tests. Laughably fast integration tests.

No relations. No scaling. No actions (for now). No secrets (for now).

• uv
• bubblewrap for the lightweight sandbox
• Docker

Run your charm's integration tests:

uv run --group integration --with jjx pytest -v tests/integration

--with jjx tells uv to install jjx in your charm's virtual environment, which exposes jjx's juju command. You don't need to manually install jjx.

# Grab a simple Kubernetes charm
git clone https://github.com/canonical/operator.git
cd operator/examples/httpbin-demo

# "Pack" the charm so its integration tests don't complain
touch fake.charm

# Go!
uv run --group integration --with jjx pytest -v tests/integration

Output:

...
collected 2 items

tests/integration/test_charm.py::test_deploy PASSED                         [ 50%]
tests/integration/test_charm.py::test_block_on_invalid_config PASSED        [100%]

---------------------------------- jubilant --------------------------------------
Models were torn down. To keep models available for subsequent test runs or manual
debugging, pass the following:
--no-juju-teardown
=============================== 2 passed in 8.41s ================================