testsuite: add test for hash_add_unique
testsuite: add test for hash_add_unique

Distrotech/kmod,lucasdemarchi/kmod,lucasdemarchi/kmod,lpereira/kmod,pmmccorm/kmod,Distrotech/kmod,lpereira/kmod,pmmccorm/kmod,lpereira/kmod,pmmccorm/kmod,Distrotech/kmod,lucasdemarchi/kmod