This commit does a few things: 1. Make the hostname update idempotent with `grep -w` 2. Add the given hostname to `/etc/hosts` as recommended by the docs 3. Add missing tests
Vagrant Core Plugins
These are plugins that ship with Vagrant. Vagrant core uses its own plugin system to power a lot of the core pieces that ship with Vagrant. Each plugin will have its own README which explains its specific role.