new_contents: from __future__ import absolute_import, division, print_function
  
  import os
  import pytest
  import procrunner
  
  def test_cosym(regression_data, run_in_tmpdir):
  
    reg_path = regression_data("multi_crystal_proteinase_k").strpath
  
    command = ['dials.cosym']
    for i in [1, 2, 3, 4, 5, 7, 8, 10]:
      command.append(os.path.join(reg_path, "experiments_"+str(i)+".json"))
      command.append(os.path.join(reg_path, "reflections_"+str(i)+".pickle"))
  
    result = procrunner.run_process(command)
    assert result['exitcode'] == 0
    assert result['stderr'] == ''
    assert os.path.exists("reindexed_reflections.pickle")
    assert os.path.exists("reindexed_experiments.json")
  
subject: Add command line test for cosym.py