NFD

sendPacket() is not really testable, unless we stub libpcap.

The old SendPacket test case used to check only the static properties (for which we already have a separate test case), and that the nOutBytes counter was properly incremented (which is no longer the responsibility of Transport subclasses, so no need to test it anymore).

sendPacket() is not really testable, unless we stub libpcap.

This is where a TUN interface based test case makes sense.

Not really... do you know how to reliably force pcap_inject() to return an error, or to perform a partial write? Using TUN might help testing the successful case, but doesn't help testing error cases (which are arguably the most interesting ones).

In any case, the old SendPacket test case did not perform this kind of checking, as I already said. So, is this task about bringing back the same level of testing as before commit cde37ad608dd5cb5e079a007445ccd5c166ee4a6 was merged, or about having full coverage for EthernetTransport? If it's the former, I'm willing to take this task; otherwise it would be substantially more complex and I'm afraid I won't have enough time for it in the near future.

This goal is to provide full coverage for EthernetTransport.

@Davide, you may add test coverage for EthernetTransport::processIncomingPacket as one step toward this goal.
After that, clear the assignee field and the rest can be done later.

sendPacket() is not really testable, unless we stub libpcap.

With the introduction of PcapHelper class, we are able to stub libpcap.
It would be necessary to move pcap_inject into PcapHelper class.
Afterwards, a stub PcapHelper can be used to test EthernetTransport.