title: codecov unable to collect data using pytest - "Coverage.py warning: No data was collected."
body: <p>I'm trying to setup codecov on my public travis repo and so far haven't been able to successfully generate a report and upload it to codecov.io. I appear to receive an erroneous report in terminal that says 0% of my code is covered along with a warning.</p>
  
  <p>as far as I can tell, my .travis.yml and shell script are perfectly inline with the conventions specified in pytest-cov and codecov's documentation.</p>
  
  <p>my travis terminal containing the full log is here: <a href="https://www.travis-ci.com/jmaggio14/imagepypelines/jobs/163802897#L681" rel="noreferrer">https://www.travis-ci.com/jmaggio14/imagepypelines/jobs/163802897#L681</a></p>
  
  <p>my repo can be found here: <a href="https://github.com/jmaggio14/imagepypelines/tree/89a6bbc2fadc94a51570d80be356941df1a87a87" rel="noreferrer">https://github.com/jmaggio14/imagepypelines/tree/89a6bbc2fadc94a51570d80be356941df1a87a87</a></p>
  
  <p>my (shortened) .travis.yml file is as follows:</p>
  
  <pre><code> sudo: false
  
    language: python
  
    python:
        - 2.7
        - 3.4
        - 3.5
        - 3.6
  
    install:
      # I removed some other lines for readability here
      - pip install codecov pytest-cov hypothesis
  
    script:
      # running tests and code coverage report
      - py.test --cov=imagepypelines tests/
  
  
    after_success:
      - codecov
  </code></pre>
  
  <p>I end up recieving the following warning and a message saying that 0% of my code is covered by my tests</p>
  
  <pre><code>Coverage.py warning: No data was collected. (no-data-collected)
  </code></pre>