Assuming you shipped your module to CPAN with working tests, test failures
from http://www.cpantesters.org/ might be due to platform issues, Perl
version issues or problems with dependencies. This module helps you
diagnose deep dependency problems by showing you exactly what modules and
versions were loaded during a test run.

When this module is loaded, it sets up an 'END' block that will take action
if the program is about to exit with a non-zero exit code or if
Test::Builder/is_passing is false by the time the 'END' block is reached.
If that happens, this module prints out the names and version numbers of
non-local modules appearing in perlvar/%INC at the end of the test.

For example: