Since there is no test method to include extension language files, a
functional test seems more appropriate.
We add a permission mask 'acl_u_foo' with translation found in extenion
'bar' and confirm that the permission language file 'permissions_foo.php'
from 'bar' was added by asserting that 'Can view foo' exists when viewing
user permissions in acp
PHPBB3-11458
NOTE: test_form_upload() is broken. Uploading files via Symfony fails to
retain $_FILES['fileupload']['type'] even if it set explicitely. This appears
to be a bug in Symfony. Since the current version of filespec::is_image()
relies on the mimetype, these tests will __fail__. filespec::is_image() has
been fixed in https://github.com/phpbb/phpbb3/pull/833 however.
PHPBB3-10941
