[basugasubaku]

Your get_tail_child always returns NULL

  for (tail_ch = head_ch; tail_ch; tail_ch = tail_ch->next);

  return tail_ch;

[uggedal]

That was embarrasing. Should be fixed now: https://github.com/uggedal/going/commit/15a83397076ffbebe585...

[jws]

Well spotted!

Going to want to add a test case with more than one child at a time. I think as is it loses all but the most recent child.