Removed User dependency

Removed user dependency from test and initialized required classes for testing. Tests are currently failing because #9 has not been merged yet.

- [x] test coverage
- [x] finish the code
- [x] gather feedback for my changes
- [x] submit changes to the documentation


| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | yes
| Tests pass?   | yes
| Fixed tickets | #9 
| Doc           | https://github.com/sulu-cmf/docs/blob/master/developer-documentation/000-foundation/testing.md