old_contents: import subprocess
  import sys
  from setuptools import setup, Command
  
  import restle
  
  
  class PyTest(Command):
      user_options = []
  
      def initialize_options(self):
          pass
  
      def finalize_options(self):
          pass
  
      def run(self):
          errno = subprocess.call([sys.executable, 'runtests.py'])
          raise SystemExit(errno)
  
  setup(
      name='restle',
      description='A REST client framework',
      keywords='rest,mapper,client',
      version=restle.__version__,
      packages=['restle'],
      requires=['six', 'requests'],
      url='https://github.com/consbio/restle',
      license='BSD',
      tests_require=['pytest', 'httpretty==0.8.6', 'mock'],
      cmdclass={'test': PyTest}
  )
  
new_contents: import subprocess
  import sys
  from setuptools import setup, Command
  
  import restle
  
  
  class PyTest(Command):
      user_options = []
  
      def initialize_options(self):
          pass
  
      def finalize_options(self):
          pass
  
      def run(self):
          errno = subprocess.call(['py.test', 'test_restle.py'])
          raise SystemExit(errno)
  
  setup(
      name='restle',
      description='A REST client framework',
      keywords='rest,mapper,client',
      version=restle.__version__,
      packages=['restle'],
      requires=['six', 'requests'],
      url='https://github.com/consbio/restle',
      license='BSD',
      tests_require=['pytest', 'httpretty==0.8.6', 'mock'],
      cmdclass={'test': PyTest}
  )
  
subject: Use py.test directly instead of through runtests.py