This commit creates a custom `read_dhcp_servers` method in the
VirtualBox 6.1 driver to handle changes made in the ouput of
`VBoxManage list dhcpservers`.
Tests for VirtualBox 6.1+ can no longer use the shared examples for the
VirtualBox 4.x driver, because the `read_dhcp_servers` change is not
backwards compatible.
This commit also creates the boilerplate for a VirtualBox 6.x shared
example in case we want to put tests there in the future.
Previously, we required a host-only interface with a static IP for NFS
to work in VirtualBox, because we needed access to the guest's IP in
order to properly configure mount commands.
After boot, VirtualBox exposes the IP addresses of a guest's network
adapters via the "guestproperty" interface.
This adds support for reading VirtualBox guest properties to the
VirtualBox driver and utilizes that support to prepare NFS settings,
which removes the necessity for a static IP for NFS to work.
In this commit we also start building out scaffolding for unit testing
vbox actions and drivers.
Test plan:
- Prepare a Vagrantfile with the following:
* private network with type: :dhcp
* synced folder with nfs: true
- Boot a VM from this Vagrantfile using the virtualbox provider
- Machine should boot successfully with working synced folder
