AddrFormatError when setting invalid interface MAC address via the API

[jeremystretch]

Environment

• Python version: 3.5.2
• NetBox version: 2.4.4

Steps to Reproduce

1. Attempt to set an invalid MAC address on an interface using the following API request:

curl -X PATCH \
-H "Authorization: Token <TOKEN>" \
-H "Content-Type: application/json" \
-H "Accept: application/json; indent=4" \
http://localhost:8000/api/dcim/interfaces/<PK>/ \
--data '{"mac_address": "01234567890123456789"}'

Expected Behavior

The API should return a validation error, as 01234567890123456789 is too long to be a valid EUI-48 address.

Observed Behavior

An unhandled AddrFormatError exception is raised.