Enable validate-config tests and add a new test

[pilou-]

ISSUE TYPE

• Bugfix Pull Request

SUMMARY

validate-config tests:

• enable existing tests
• add a new test

Depends-On: #882

[pilou-]

Pull request rebased (conflict fixed)

[pilou-]

@Voronenko could you review this one ?

Extract from build log (17 passed in 1.91 seconds):

TASK [validate-config : Cat output] ********************************************
[1;30mtask path: /home/travis/build/ansible/ansible-container/test/includes/show-output.yml:3[0m
[0;34mUsing module file /home/travis/virtualenv/python2.7.13/lib/python2.7/site-packages/ansible/modules/commands/command.py[0m
[...]
[0;33mchanged: [localhost] => {[0m
[0;33m    "changed": true, [0m
[0;33m    "cmd": [[0m
[0;33m        "cat", [0m
[0;33m        "./task.output"[0m
[0;33m    ], [0m
[0;33m    "delta": "0:00:00.004054", [0m
[0;33m    "end": "2018-06-20 08:12:02.068743", [0m
[0;33m    "invocation": {[0m
[0;33m        "module_args": {[0m
[0;33m            "_raw_params": "cat \"./task.output\"", [0m
[0;33m            "_uses_shell": false, [0m
[0;33m            "chdir": null, [0m
[0;33m            "creates": null, [0m
[0;33m            "executable": null, [0m
[0;33m            "removes": null, [0m
[0;33m            "stdin": null, [0m
[0;33m            "warn": true[0m
[0;33m        }[0m
[0;33m    }, [0m
[0;33m    "rc": 0, [0m
[0;33m    "start": "2018-06-20 08:12:02.064689", [0m
[0;33m    "stderr": "", [0m
[0;33m    "stderr_lines": [], [0m
[0;33m    "stdout": "============================= test session starts ==============================\nplatform linux2 -- Python 2.7.13, pytest-3.2.1, py-1.4.34, pluggy-0.4.0\nrootdir: /home/travis/build/ansible/ansible-container, inifile:\ncollected 17 items\n\n../../test/tests/validate_config.py .................\n\n========================== 17 passed in 1.91 seconds ===========================", [0m
[0;33m    "stdout_lines": [[0m
[0;33m        "============================= test session starts ==============================", [0m
[0;33m        "platform linux2 -- Python 2.7.13, pytest-3.2.1, py-1.4.34, pluggy-0.4.0", [0m
[0;33m        "rootdir: /home/travis/build/ansible/ansible-container, inifile:", [0m
[0;33m        "collected 17 items", [0m
[0;33m        "", [0m
[0;33m        "../../test/tests/validate_config.py .................", [0m
[0;33m        "", [0m
[0;33m        "========================== 17 passed in 1.91 seconds ==========================="[0m
[0;33m    ][0m

[Voronenko]

@pilou- What issue no PR refers to, if any ?

[pilou-]

@Voronenko this pull-request:

• fix and enable existing validate-config tests
• add a new unit test: test_get_dependencies_for_role

[pilou-]

@gregdek could you merge this one ?