printf("\"%s\" → \"%s\"\n", input, p);
assert_se(streq(p, output));
printf("\"%s\" → \"%s\"\n", input, p);
assert_se(streq(p, output));
u = now(CLOCK_REALTIME);
r = calendar_spec_next_usec(c, u, &u);
printf("Next: %s\n", r < 0 ? strerror(-r) : format_timestamp(buf, sizeof(buf), u));
u = now(CLOCK_REALTIME);
r = calendar_spec_next_usec(c, u, &u);
printf("Next: %s\n", r < 0 ? strerror(-r) : format_timestamp(buf, sizeof(buf), u));