ModuleNotFoundError: No module named 'netifaces' during netplan tests

[Jonathan Cave]

If you try to run any of the tests in wireless-netplan-automated on Ubuntu Core 18 with checkbox core snap 1.4 the following import error will occur when trying to call the netplan command

Traceback (most recent call last):
  File "/usr/sbin/netplan", line 23, in <module>
    netplan.main()
  File "/usr/share/netplan/netplan/cli/core.py", line 42, in main
    self.parse_args()
  File "/usr/share/netplan/netplan/cli/core.py", line 35, in parse_args
    import netplan.cli.commands
  File "/usr/share/netplan/netplan/cli/commands/__init__.py", line 18, in <module>
    from netplan.cli.commands.apply import NetplanApply
  File "/usr/share/netplan/netplan/cli/commands/apply.py", line 29, in <module>
    import netifaces
ModuleNotFoundError: No module named 'netifaces'
ERROR: failed netplan apply call