old_contents: # This is imported from setup.py and the test script
  tests_require = [
      'pytest',
      'pytest-capturelog',
      'pytest-cov',
  ]
  
new_contents: # This is imported from setup.py and the test script
  tests_require = [
      'coveralls',
      'pytest',
      'pytest-capturelog',
      'pytest-cov',
  ]
  
subject: Add coveralls to test requirements