Tests break for me on python3.7

I'm getting a RuntimeError for all tests with Python3, I'm using the
wrapped pytest executable 'run_tests.py' as attached below, I asume the
wrapper doesn't work with newer python3 versions (I've recently upgraded
to debian stable aka buster, the previous version came with python3.5).

Can someone enlighten me how to call the tests without that wrapper?
Should we ship two versions of the wrapper, one for older, one for newer
versions of python?

Ralf

Error messages seen:

% python3 run_tests.py
============================= test session starts ==============================
platform linux -- Python 3.7.3, pytest-2.9.2, py-1.4.31, pluggy-0.3.1
rootdir: /home/ralf/checkout/sourceforge/roundup.hg.tip, inifile:
collected 0 items / 28 errors

==================================== ERRORS ====================================
____________________ ERROR collecting test/test_actions.py _____________________
_pytest.runner:150: in __init__
    ???
_pytest.main:435: in _memocollect
    ???
_pytest.main:315: in _memoizedcall
    ???
_pytest.main:435: in <lambda>
    ???
_pytest.python:605: in collect
    ???
_pytest.python:459: in collect
    ???
_pytest.python:471: in makeitem
    ???
_pytest.vendored_packages.pluggy:724: in __call__
    ???
_pytest.vendored_packages.pluggy:338: in _hookexec
    ???
_pytest.vendored_packages.pluggy:333: in <lambda>
    ???
_pytest.vendored_packages.pluggy:595: in execute
    ???
_pytest.vendored_packages.pluggy:249: in _wrapped_call
    ???
E   RuntimeError: generator raised StopIteration
_____________________ ERROR collecting test/test_admin.py ______________________
...

-- 
Dr. Ralf Schlatterbeck                  Tel:   +43/2243/26465-16
Open Source Consulting                  www:   http://www.runtux.com
Reichergasse 131, A-3411 Weidling       email: [email protected]