old_contents: # This is a minimal setup script intended just for building PEX.
  # Generate cdx_writer.pex with:
  #   pex -r requirements.txt -o cdx_writer.pex -m cdx_writer .
  from setuptools import setup
  
  setup(
      name='CDX-Writer',
      version='0.3.1',
      py_modules=['cdx_writer'],
      )
  
new_contents: # This is a minimal setup script intended just for building PEX.
  # Generate cdx_writer.pex with:
  #   pex -r requirements.txt -o cdx_writer.pex -m cdx_writer .
  from setuptools import setup
  
  setup(
      name='CDX-Writer',
      version='0.3.1',
      py_modules=['cdx_writer'],
      etras_require={
          'test': [
              'pytest<5;python_version<"3"',
              'pytest;python_version>="3"'
          ]
      }
  )
  
subject: add extras_require for testing