# Juju

> Juju is an open source orchestration engine for deploying, integrating, and managing applications across Kubernetes, VMs, and bare metal using software operators called charms.


2026 CC-BY-SA, Canonical Ltd.

## Pages in this subsection

- [Unit testing](https://documentation.ubuntu.com/juju/4.0/contributor/reference/testing/unit-testing.md): Learn about unit testing in Juju with gocheck package, including test suites, checkers, and util suite composition patterns.
- [Checker](https://documentation.ubuntu.com/juju/4.0/contributor/reference/testing/unit-testing/checker.md): Use gocheck checkers for assertions in Juju unit tests, including IsNil, Equals, DeepEquals, and ErrorMatches patterns.
- [Unit test suite](https://documentation.ubuntu.com/juju/4.0/contributor/reference/testing/unit-testing/unit-test-suite.md): Create structured unit test suites with distinct setup and teardown logic using util suite composition for Juju testing.
- [Util suite](https://documentation.ubuntu.com/juju/4.0/contributor/reference/testing/unit-testing/util-suite.md): Leverage util suites like BaseSuite and FakeHomeSuite for structured test setup, teardown, and environment isolation in Juju.

## Optional

- [Top-level llms.txt](https://documentation.ubuntu.com/juju/4.0/llms.txt): Complete documentation index.