The order of precedence of configuration files for PHPUnit is:
 - phpunit.xml (allowing custom user defined configuration)
 - phpunit.xml.dist (configuration distributed with the software)

we don't want to check performance just yet. we just want to make jenkins end more reliably.

Cache Test: set datadir to temporary location, otherwise initmountpoints will access to productive location

Added a second storage and cache Object to simulate a second user.