This commit adds integration tests to headscale. They are currently
quite simple, but it lays the groundwork for more comprehensive testing
and ensuring we dont break things with the official tailscale client.
The test works by leveraging Docker (via dockertest) to spin up a
Headscale container, and a number of tailscale containers (10).
Each tailscale container is joined to the headscale and then "passed on"
to the tests.
Currently three tests have been implemented:
- Have all tailscale containers join headscale (in the setup process)
- Get IP from each container (I plan to extend this with cross-ping)
- List nodes with headscales CLI and verify all has been registered
This test depends on Docker, and currently, I have not looked into
hooking it into Github Actions.
