<document source="test data">
<system_message level="1" line="1" source="test data" type="INFO">
<paragraph>
Possible incomplete section title.
Treating the overline as ordinary text because it's so short.
<definition_list>
<definition_list_item>
<term>
==
<definition>
<paragraph>
Not a title: a definition list item.
<definition_list_item>
<term>
--
<definition>
<paragraph>
Another definition list item. It's in a different list,
but that's an acceptable limitation given that this will
probably never happen in real life.
<paragraph>
The next line will trigger a warning:
<system_message level="2" line="9" source="test data" type="WARNING">
<paragraph>
Definition list ends without a blank line; unexpected unindent.
<paragraph>
==