Add functional test for receiving a diagnostic response.
Add functional test for receiving a diagnostic response.

mgiannikouris/vi-firmware,openxc/vi-firmware,openxc/vi-firmware,ene-ilies/vi-firmware,openxc/vi-firmware,mgiannikouris/vi-firmware,ene-ilies/vi-firmware,ene-ilies/vi-firmware,ene-ilies/vi-firmware,openxc/vi-firmware,mgiannikouris/vi-firmware,mgiannikouris/vi-firmware