pipe_write
static int pipe_write(file_t *, off_t *, struct uio *, kauth_cred_t, int);
.fo_write = pipe_write,
ATF_TC(pipe_write);
ATF_TC_HEAD(pipe_write, tc)
ATF_TC_BODY(pipe_write, tc)
ATF_TP_ADD_TC(tp, pipe_write);