# 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 - [Write tests](https://documentation.ubuntu.com/juju/3.6/contributor/howto/write-tests.md): How to write tests for Juju using go test and gocheck, including unit and integration testing best practices for contributors. ## Optional - [Top-level llms.txt](https://documentation.ubuntu.com/juju/3.6/llms.txt): Complete documentation index.