old_contents: """
  Tests for the qopen package.
  
  qopen-runtests [-h] [-v] [-a] [-p] [-d] [-f] [-n num]
  
  -h    short help
  -v    be verbose
  -a    run all tests
  -p    use a permanent tempdir
  -d    empty permanent tempdir at start
  -f    fail fast
  -n num   maximal number of cores to use (default: all)
  """
  
  from pkg_resources import resource_filename
  import sys
  import unittest
  
  import matplotlib
  matplotlib.use('agg')
  
  
  def run():
      args = sys.argv[1:]
      if '-h' in args:
          print(__doc__)
          return
      loader = unittest.TestLoader()
      test_dir = resource_filename('qopen', 'tests')
      suite = loader.discover(test_dir)
      runner = unittest.runner.TextTestRunner(failfast='-f' in args)
      ret = not runner.run(suite).wasSuccessful()
      sys.exit(ret)
  
new_contents: """
  Tests for the qopen package.
  
  qopen-runtests [-h] [-v] [-a] [-p] [-d] [-f] [-n num]
  
  -h    short help
  -v    be verbose
  -a    run all tests
  -p    use a permanent tempdir
  -d    empty permanent tempdir at start
  -f    fail fast
  -n num   maximal number of cores to use (default: all)
  """
  
  from pkg_resources import resource_filename
  import sys
  import unittest
  
  
  def run():
      args = sys.argv[1:]
      if '-h' in args:
          print(__doc__)
          return
      loader = unittest.TestLoader()
      test_dir = resource_filename('qopen', 'tests')
      suite = loader.discover(test_dir)
      runner = unittest.runner.TextTestRunner(failfast='-f' in args)
      ret = not runner.run(suite).wasSuccessful()
      sys.exit(ret)
  
subject: remove init of mpl backend in tests