valgrind reports leaked (though still reachable) memory. I invoke it like this, from librepo/build/tests:

CK_FORK=no valgrind --leak-check=full --show-reachable=yes ./test_main ../../tests/test_data/

Some of these might be known GPGME leaks (see e.g. [1]), others might be real. Ideally, a fix for this will include a valgrind suppressions file checked into the upstream repo, which will contain those leaks that librepo can do nothing about. That way we can run valgrind with it occasionally and be sure nothing unexpected is happening to the memory.

[1] https://mailman.archlinux.org/pipermail/pacman-dev/2011-June/013398.html