title: Using pytest-cov plugin from inside PyCharm
body: <p>I want to use pytest and pytest-cov plugin from inside PyCharm, so I added <code>--cov=package</code> to "Additional arguments" entry field when I edited my configuration. However, I get both the output and the error, not sure why:</p>
  
  <pre><code>Testing started at 4:50 PM ...
  /home/alex/.repos/codelib/github/dsa/env/bin/python /home/alex/Downloads/pycharm-2019.3.4/plugins/python/helpers/pycharm/_jb_pytest_runner.py --path /home/alex/.repos/codelib/github/dsa/ -- --cov=bag
  Launching pytest with arguments --cov=bag /home/alex/.repos/codelib/github/dsa/ in /home/alex/.repos/codelib/github/dsa/bag/tests
  
  ============================= test session starts ==============================
  platform linux -- Python 3.6.9, pytest-5.4.1, py-1.8.1, pluggy-0.13.1 -- /home/alex/.repos/codelib/github/dsa/env/bin/python
  cachedir: .pytest_cache
  rootdir: /home/alex/.repos/codelib/github/dsa
  plugins: cov-2.8.1
  collecting ... collected 1 item
  
  test_simple_bag.py::test_len PASSED                                      [100%]
  
  Coverage statistics reporting failed
  Traceback (most recent call last):
    File "/home/alex/Downloads/pycharm-2019.3.4/plugins/python/helpers/pycharm/teamcity/pytest_plugin.py", line 371, in pytest_terminal_summary
      self._report_coverage()
    File "/home/alex/Downloads/pycharm-2019.3.4/plugins/python/helpers/pycharm/teamcity/pytest_plugin.py", line 378, in _report_coverage
      from coverage.report import Reporter
  ImportError: cannot import name 'Reporter'
  
  
  ----------- coverage: platform linux, python 3.6.9-final-0 -----------
  Name                                                     Stmts   Miss  Cover
  ----------------------------------------------------------------------------
  /home/alex/.repos/codelib/github/dsa/bag/__init__.py         0      0   100%
  /home/alex/.repos/codelib/github/dsa/bag/simple_bag.py      17      5    71%
  __init__.py                                                  0      0   100%
  test_simple_bag.py                                           6      0   100%
  ----------------------------------------------------------------------------
  TOTAL                                                       23      5    78%
  
  
  ============================== 1 passed in 0.03s ===============================
  
  Process finished with exit code 0
  </code></pre>
  
  <p>When I run tests from the terminal, everything goes fine:</p>
  
  <pre><code>(env) alex@smartalex-pc:~/.repos/codelib/github/dsa$ pytest --cov=bag
  ============================================== test session starts ===============================================
  platform linux -- Python 3.6.9, pytest-5.4.1, py-1.8.1, pluggy-0.13.1
  rootdir: /home/alex/.repos/codelib/github/dsa
  plugins: cov-2.8.1
  collected 1 item                                                                                                 
  ​
  bag/tests/test_simple_bag.py .                                                                             [100%]
  ​
  ----------- coverage: platform linux, python 3.6.9-final-0 -----------
  Name                           Stmts   Miss  Cover
  --------------------------------------------------
  bag/__init__.py                    0      0   100%
  bag/simple_bag.py                 17      5    71%
  bag/tests/__init__.py              0      0   100%
  bag/tests/test_simple_bag.py       6      0   100%
  --------------------------------------------------
  TOTAL                             23      5    78%
  ​
  ​
  =============================================== 1 passed in 0.03s ================================================
  (env) alex@smartalex-pc:~/.repos/codelib/github/dsa$ 
  </code></pre>