This doesn't happen to me with php5 but does with HHVM and roles translate + cirrussearch (or gettingstarted, which implies cirrussearch) enabled. Once I disabled cirrussearch and gettingstarted, the test was skipped correctly, "No test TTMServer available".
Niklas said "I think CirrusSearch should disable itself when it detects unit tests are being run".
vagrant@nemobis:/srv/vagrant/mediawiki/tests/phpunit$ php phpunit.php suites/ExtensionsTestSuite.php [...] PHPUnit 3.7.37 by Sebastian Bergmann. [...] There were 2 errors: 1) SolrTTMServerTest::testSearchableTTMServer BadMethodCallException: Call to a member function getMessage() on a non-object (NULL) /srv/vagrant/mediawiki/extensions/Translate/tag/TranslatablePage.php:253 /srv/vagrant/mediawiki/extensions/Translate/tag/PageTranslationHooks.php:47 /srv/vagrant/mediawiki/includes/Hooks.php:206 /srv/vagrant/mediawiki/includes/GlobalFunctions.php:4031 /srv/vagrant/mediawiki/includes/parser/Parser.php:402 /srv/vagrant/mediawiki/includes/content/WikitextContent.php:327 /srv/vagrant/mediawiki/includes/content/AbstractContent.php:486 /srv/vagrant/mediawiki/extensions/CirrusSearch/includes/Updater.php:410 /srv/vagrant/mediawiki/extensions/CirrusSearch/includes/Updater.php:330 /srv/vagrant/mediawiki/extensions/CirrusSearch/includes/Updater.php:192 /srv/vagrant/mediawiki/extensions/CirrusSearch/includes/Updater.php:67 /srv/vagrant/mediawiki/extensions/CirrusSearch/includes/Job/LinksUpdate.php:48 /srv/vagrant/mediawiki/extensions/CirrusSearch/includes/Job/Job.php:55 /srv/vagrant/mediawiki/extensions/Translate/tests/phpunit/SolrTTMServerTest.php:176 /srv/vagrant/mediawiki/extensions/Translate/tests/phpunit/SolrTTMServerTest.php:36 /srv/vagrant/mediawiki/tests/phpunit/MediaWikiTestCase.php:133 /srv/vagrant/mediawiki/tests/phpunit/MediaWikiPHPUnitCommand.php:42 /srv/vagrant/mediawiki/tests/phpunit/phpunit.php:160
Version: unspecified
Severity: normal
See Also: T69295: Fatal error: Call to a member function getMessage() on a non-object in /mediawiki/extensions/Translate/tag/TranslatablePage.php on line 253