I know it's a really specific problem - may be without solutions - I post this in case some body has an idea:
While running phpunit tests for Moodle 2.9.3 on mac os10.9.5 and php5.5.10 I got a Segmentation fault: 11 message on this line :
<testsuite name="filter_mediaplugin_testsuite">
<directory suffix="_test.php">filter/mediaplugin/tests</directory>
</testsuite>
Thanks in advance,