I started porting the IPv6 Regression tests from the OpenBSD project  to FreeBSD. This change includes the fragmentation tests to Kyua and uses ATF test; i.e. they can be run by running make check. Each tests spins up a jail, configures ipv6 and sends ICMP packets in order to test various aspects of the fragmentation functionality.
Other tests can also be ported but require more work.
Requirements: VNET, python2, scapy.