Write MAC spoofing tests

Once implemented in Tails, we’ll have to write a test to verify it’s working.

Feature Branch: test/6302-mac-spoofing

Parent Task: #6298 (closed)

Related issues

• Related to #7546 (closed)
• Blocked by #5421 (closed)
• Blocked by #10160 (closed)
• Blocks #10336 (closed)
• Blocked by #6094 (closed)
• Blocks #10340 (closed)

Original created by @bertagaz on 6302 (Redmine)