@lyrixx `doctrine-bundle` is only needed to run the tests. It's a `require-dev` dependency.
Making it a soft dependency is awkward because all functional tests on the ACL system will be skipped by default.
If someone clone the repository, start hacking, run phpunit and make a PR, he can silently broke the ACL system.

It will also require to tweak `.travis.yml` (to make Travis install `doctrine-bundle` before running the tests) and update the doc to explain that tests should be run with `doctrine-bundle` installed.

If it's really annoying to have `doctrine-bundle` as a development dependency, I prefer registering the DBAL connection directly in the test app's kernel.