old_contents: import os
  from subprocess import check_call
  
  REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
  os.chdir(REPO_ROOT)
  
  os.putenv('PATH', '{}:{}'.format(os.path.join(REPO_ROOT, 'bin'), os.getenv('PATH')))
  os.putenv('DVC_HOME', REPO_ROOT)
  
  cmd = 'nosetests -v --processes=-1 --process-timeout=200 --cover-inclusive --cover-erase --cover-package=dvc --with-coverage'
  check_call(cmd, shell=True)
  
new_contents: import os
  from subprocess import check_call
  
  REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
  os.chdir(REPO_ROOT)
  
  os.putenv('PATH', '{}:{}'.format(os.path.join(REPO_ROOT, 'bin'), os.getenv('PATH')))
  os.putenv('DVC_HOME', REPO_ROOT)
  os.putenv('DVC_TEST', 'true')
  
  cmd = 'nosetests -v --processes=-1 --process-timeout=200 --cover-inclusive --cover-erase --cover-package=dvc --with-coverage'
  check_call(cmd, shell=True)
  
subject: define DVC_TEST env variable