The tests of python-requests 2.21.0 are not compatible with pytest 4.

+ /usr/bin/python2 -m pytest -v
============================= test session starts ==============================
platform linux2 -- Python 2.7.16, pytest-4.3.1, py-1.7.0, pluggy-0.9.0 -- /usr/bin/python2
cachedir: .pytest_cache
rootdir: /builddir/build/BUILD/requests-2.21.0, inifile: pytest.ini
plugins: mock-1.10.3, cov-2.6.1
collecting ... collected 524 items / 1 errors / 523 selected

==================================== ERRORS ====================================
_____________________ ERROR collecting tests/test_utils.py _____________________
/usr/lib/python2.7/site-packages/pluggy/hooks.py:289: in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
/usr/lib/python2.7/site-packages/pluggy/manager.py:68: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
/usr/lib/python2.7/site-packages/pluggy/manager.py:62: in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
/usr/lib/python2.7/site-packages/_pytest/python.py:226: in pytest_pycollect_makeitem
    res = list(collector._genfunctions(name, obj))
/usr/lib/python2.7/site-packages/_pytest/python.py:402: in _genfunctions
    self.ihook.pytest_generate_tests(metafunc=metafunc)
/usr/lib/python2.7/site-packages/pluggy/hooks.py:289: in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
/usr/lib/python2.7/site-packages/pluggy/manager.py:68: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
/usr/lib/python2.7/site-packages/pluggy/manager.py:62: in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
/usr/lib/python2.7/site-packages/_pytest/python.py:133: in pytest_generate_tests
    metafunc.parametrize(*marker.args, **marker.kwargs)
/usr/lib/python2.7/site-packages/_pytest/python.py:994: in parametrize
    function_definition=self.definition,
/usr/lib/python2.7/site-packages/_pytest/mark/structures.py:113: in _for_parametrize
    if len(param.values) != len(argnames):
E   TypeError: object of type 'MarkDecorator' has no len()
!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!!
=========================== 1 error in 1.43 seconds ============================
error: Bad exit status from /var/tmp/rpm-tmp.XQdbpx (%check)

This is because of https://docs.pytest.org/en/latest/deprecations.html#marks-in-pytest-mark-parametrize