When running CirrusSearch unit tests under HHVM, the build fails with:
Fatal error: File not found: PEAR.php in mwext-CirrusSearch-testextension-hhvm/src/extensions/TimedMediaHandler/handlers/OggHandler/PEAR/File_Ogg/File/Ogg.php on line 123
Jenkins job: https://integration.wikimedia.org/ci/job/mwext-CirrusSearch-testextension-hhvm/
We do have the Debian package `php-pear` installed which install the files under `/usr/share/php/`. HHVM does not have that directory in its include path.