title: pytest and codecov: no coverage report found
body: <p>I have created a brand new <a href="https://github.com/neuropsychology/NeuroKit" rel="nofollow noreferrer">Python repository</a> based on a cookie-cutter template. Everything looks okay, so I am trying now to set the testing and testing coverage using travis and codecov. I am new to pytest but I am trying to do things right. After looking on the internet, I ended up with this setup:</p>
  
  <p>In <a href="https://github.com/neuropsychology/NeuroKit/blob/master/.travis.yml" rel="nofollow noreferrer"><code>.travis.yml</code></a>, I have added the following:</p>
  
  <pre><code>install: 
    - pip install -U tox-travis
    - pip install coverage
    - pip install codecov
  
  script:
      - python setup.py install
      - tox
      - coverage run tests/test_foo.py
  </code></pre>
  
  <p>In my <a href="https://github.com/neuropsychology/NeuroKit/blob/master/tox.ini" rel="nofollow noreferrer"><code>tox.ini</code></a> file:</p>
  
  <pre><code>[testenv]
  passenv = CI TRAVIS TRAVIS_*
  setenv =
      PYTHONPATH = {toxinidir}
      PIPENV_IGNORE_VIRTUALENVS=1
  deps =
      pipenv
      codecov
      pytest
      {py27}: pathlib2
  commands_pre = 
      pipenv install --dev --skip-lock
      codecov
  </code></pre>
  
  <p>I have created a minimal <a href="https://github.com/neuropsychology/NeuroKit/blob/master/tests/test_foo.py" rel="nofollow noreferrer"><code>tests/test_foo.py</code></a> file with the following (<code>foo()</code> is the only function currently present in the package).</p>
  
  <pre class="lang-py prettyprint-override"><code>import pytest
  import doctest
  import neurokit2 as nk
  
  if __name__ == '__main__':
      doctest.testmod()
      pytest.main()
  
  def test_foo():
      assert nk.foo() == 4
  </code></pre>
  
  <p>I have It seems that codecov, triggered by travis does not run through the test. Moreover, on travis, it says <a href="https://travis-ci.org/neuropsychology/NeuroKit/jobs/604805529#L332" rel="nofollow noreferrer"><code>Error: No coverage report found</code></a>  I wonder what am I doing wrong?</p>