ATF is the automatic test framework for NetBSD. We strive to have automatic tests for all the important parts of our system: libraries, syscalls, binaries, etc.
Your task is to write such tests. You should read the ?tutorial about how to write an atf test, and then you can start testing things.
As testing is an endless task, here are just a few ideas about which items could be tested:

atomic_ops(3)

cdbr(3) and cdbw(3)

inet(3) and inet_net(3)

ethers(3) , iso_addr(3) and link_addr(3)

strtol(3) , strtoul(3) and strtoull(3)

uuid(3)

Though this task is originally rather considered quality assurance, the actual test writing is only coding work (whether the test succeeds or not, is up to the original author of the library or tool).
The tests should be written in either C or sh, depending on the test subject.

Every single written test is considered as one task. If you think there is another test that should be added, but is not listed here, feel free to contact us. This task can be fulfilled multiple times and will be recreated once it is claimed.



Link to the wiki article describing atf: http://wiki.netbsd.org/tutorials/atf/