def test_combine_run_params(self):
     params = {
         'param1': [1, 2, 3],
         'param2': [4, 5],
         'param3': [6],
         'param4': None
     }
     combs = BulkRun._combine_run_params(params)
     #
     assert len(combs) == 6
     assert set(combs[0].keys()) == set(['param3', 'param2', 'param1'])
     assert set(combs[0].values()) == set([6, 4, 1])
     assert set(combs[-1].values()) == set([6, 5, 3])