Test: Fix failing coverage

[matham]

The coverage error was

 Traceback (most recent call last):
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\_pytest\main.py", line 191, in wrap_session
     session.exitstatus = doit(config, session) or 0
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\_pytest\main.py", line 247, in _main
     config.hook.pytest_runtestloop(session=session)
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\pluggy\hooks.py", line 286, in __call__
     return self._hookexec(self, self.get_hookimpls(), kwargs)
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\pluggy\manager.py", line 93, in _hookexec
     return self._inner_hookexec(hook, methods, kwargs)
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\pluggy\manager.py", line 87, in <lambda>
     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\pluggy\callers.py", line 203, in _multicall
     gen.send(outcome)
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\pytest_cov\plugin.py", line 264, in pytest_runtestloop
     self.cov_controller.finish()
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\pytest_cov\engine.py", line 46, in ensure_topdir_wrapper
     return meth(self, *args, **kwargs)
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\pytest_cov\engine.py", line 231, in finish
     self.cov.stop()
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\coverage\control.py", line 687, in combine
     combine_parallel_data(self._data, aliases=aliases, data_paths=data_paths, strict=strict)
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\coverage\data.py", line 117, in combine_parallel_data
     data.update(new_data, aliases=aliases)
   File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\coverage\sqldata.py", line 561, in update
     raise CoverageException("Can't combine arc data with line data")
 coverage.misc.CoverageException: Can't combine arc data with line data