There are currently some testsuites/testcases that are decorated with
"requires_2_links" but in reality there is no logic associated with having 2
physical ports on the SUT. These testsuites just configure the SUT ports (even
if it's just 1) according to the testsuite requirements, and then
ingress/egress based on topology.ingress_port and topology.egress_port. For
these testsuites/testcases, we should rewrite their decorator to
"requires_1_link."

So, assess the whole list of testcases and submit a patch rewriting their
decorators.