chore(tox): Update pytest call for more verbosity, end quickly

Author: effigies

tox.ini

@@ -36,8 +36,8 @@ pass_env =
   NIFREEZE_WERRORS
 extras = test
 commands =
-  pytest --doctest-modules --cov nifreeze -n auto --cov-report xml \
-  --junitxml=test-results.xml -v src test {posargs}
+  pytest -svx --doctest-modules --cov nifreeze --cov-report xml \
+  --junitxml=test-results.xml -v src test {posargs:-n auto}
 
 [testenv:notebooks]
 description = Run notebooks