base.py

@pytest.fixture()
def app():
    app = create_app(TestingConfig)

    return app

result:

==================================================================== test session starts =====================================================================
platform linux2 -- Python 2.7.5, pytest-3.3.1, py-1.5.2, pluggy-0.6.0
rootdir: /home/senaps/Projects/pers/flask-bare/code, inifile:
collected 4 items                                                                                                                                            

tests/test_config.py ...                                                                                                                               [ 75%]
tests/test_main_bluprint.py E                                                                                                                          [100%]

=========================================================================== ERRORS ===========================================================================
___________________________________________________________ ERROR at setup of TestMain.test_index ____________________________________________________________
file /home/senaps/Projects/pers/flask-bare/code/tests/test_main_bluprint.py, line 8
      def test_index(self, client):
E       fixture 'client' not found
>       available fixtures: app, cache, capfd, capfdbinary, caplog, capsys, capsysbinary, doctest_namespace, monkeypatch, pytestconfig, record_xml_property, recwarn, tmpdir, tmpdir_factory
>       use 'pytest --fixtures [testpath]' for help on them.

/home/senaps/Projects/pers/flask-bare/code/tests/test_main_bluprint.py:8
============================================================= 3 passed, 1 error in 0.02 seconds ==================================

test_main

class TestMain:

    def test_index(self, client):
        res = app.client.get(url_for('main.index'))
        assert res.status_code == 200