The relevant formatting rule from the tree-construction README:

> Each test must begin with a string "\#data" followed by a newline (LF).
> All subsequent lines until a line that says "\#errors" are the test data
> and must be passed to the system being tested unchanged, except with the
> final newline (on the last line) removed.
>
> Then there must be a line that says "\#errors".

Commit 56d589a placed `#errors` after `#document-fragment`