Feature: Features could be tagged
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

For picking up tests to run we can use `tests
selection <http://pytest.org/latest/usage.html#specifying-tests-selecting-tests>`__
technique. The problem is that you have to know how your tests are
organized, knowing only the feature files organization is not enough.
`cucumber tags <https://github.com/cucumber/cucumber/wiki/Tags>`__
introduces standard way of categorizing your features and scenarios.

Rule:
'''''

Background:
           

-  Given File "Passed.feature" with content:

   .. code:: gherkin

      @passed
      Feature: Steps are executed by corresponding step keyword decorator
        Scenario: Passed
          Given I produce passed test

-  Given File "Failed.feature" with content:

   .. code:: gherkin

      @failed
      Feature: Steps are executed by corresponding step keyword decorator
        Scenario: Failed
          Given I produce failed test

-  Given File "Both.feature" with content:

   .. code:: gherkin

      @both
      Feature: Steps are executed by corresponding step keyword decorator
        Scenario: Passed
          Given I produce passed test

        Scenario: Failed
          Given I produce failed test

-  Given File "pytest.ini" with content:

   .. code:: ini

      [pytest]
      markers =
        passed
        failed
        both

-  And File "conftest.py" with content:

   .. code:: python

      from pytest_bdd.compatibility.pytest import fail
      from pytest_bdd import given

      @given('I produce passed test')
      def passing_step():
        ...

      @given('I produce failed test')
      def failing_step():
        fail('Enforce fail')

Scenario: Run pytest with marker passed
                                       

-  When run pytest

   ======== == ======
   cli_args -m passed
   ======== == ======
   ======== == ======

-  Then pytest outcome must contain tests with statuses:

   ====== ======
   passed failed
   ====== ======
   1      0
   ====== ======

Scenario: Run pytest with marker failed
                                       

-  When run pytest

   ======== == ======
   cli_args -m failed
   ======== == ======
   ======== == ======

-  Then pytest outcome must contain tests with statuses:

   ====== ======
   passed failed
   ====== ======
   0      1
   ====== ======

Scenario: Run pytest with marker passed or failed
                                                 

-  When run pytest

   ======== == ================
   cli_args -m passed or failed
   ======== == ================
   ======== == ================

-  Then pytest outcome must contain tests with statuses:

   ====== ======
   passed failed
   ====== ======
   1      1
   ====== ======

Scenario: Run pytest with marker not both
                                         

-  When run pytest

   ======== == ========
   cli_args -m not both
   ======== == ========
   ======== == ========

-  Then pytest outcome must contain tests with statuses:

   ====== ======
   passed failed
   ====== ======
   1      1
   ====== ======

Scenario: Run pytest with marker both
                                     

-  When run pytest

   ======== == ====
   cli_args -m both
   ======== == ====
   ======== == ====

-  Then pytest outcome must contain tests with statuses:

   ====== ======
   passed failed
   ====== ======
   1      1
   ====== ======

Scenario: Run pytest with no marker
                                   

-  When run pytest

-  Then pytest outcome must contain tests with statuses:

   ====== ======
   passed failed
   ====== ======
   2      2
   ====== ======