* '''PYTEST_PROCESSES_SAUCE''' - Number of parallel py.test processes to use on [http://saucelabs.com/ Sauce Labs] jobs.
* '''PYTEST_PROCESSES_WINDOWS''' - Number of parallel py.test processes to use on Windows nodes.
* '''PYTEST_RERUNS''' - Number of times to rerun a failed test (used by pytest-rerunfailures).
= Upgrading =