PDFUnit comes with the utility ExtractBookmarks which exports bookmarks from PDF documents into an XML file. Chapter 3.5: “Bookmarks and Named Destinations” describes how to use this created XML file for bookmark tests.

::
:: Extract bookmarks from a PDF document into an XML file
::

@echo off
setlocal
set CLASSPATH=./lib/aspectj-1.8.7/*;%CLASSPATH%
set CLASSPATH=./lib/bouncycastle-jdk15on-153/*;%CLASSPATH%
set CLASSPATH=./lib/commons-collections4-4.1/*;%CLASSPATH%
set CLASSPATH=./lib/commons-logging-1.2/*;%CLASSPATH%
set CLASSPATH=./lib/pdfbox-2.0.0/*;%CLASSPATH%
set CLASSPATH=./lib/pdfunit-2016.05/*;%CLASSPATH%

set TOOL=com.pdfunit.tools.ExtractBookmarks
set OUT_DIR=./tmp
set IN_FILE=diverseContentOnMultiplePages.pdf
set PASSWD=

java  %TOOL%  %IN_FILE%  %OUT_DIR%  %PASSWD%
endlocal

The file diverseContentOnMultiplePages.pdf contains 4 bookmarks:

The output file _bookmarks_diverseContentOnMultiplePages.out.xml can be used a an information base for tests:

<?xml version="1.0" encoding="utf-8"?>
<bookmarks>
  <bookmark label="Content on first page." page="1" />
  <bookmark label="Content on page 2."     page="2" />
  <bookmark label="Content on page 3."     page="3" />
  <bookmark label="Content on last page."  page="4" />
</bookmarks>