reintroduce old testing mode for run.py
reintroduce old testing mode for run.py

tjwei/jedi,mfussenegger/jedi,tjwei/jedi,mfussenegger/jedi,dwillmer/jedi,flurischt/jedi,WoLpH/jedi,jonashaag/jedi,dwillmer/jedi,jonashaag/jedi,flurischt/jedi,WoLpH/jedi