What triggers a worker to call teardown_class?

[vitaly-krugl]

I am working on a new experimental pytest-xdist scheduler plugin. I need some guidance regarding which specific condition(s) trigger workers to call cleanup functions such as teardown_class.

For example, my test classes have the teardown_class(cls) classmethod. How does the worker determine when teardown_class should be called for a specific test class? In other words, which specific condition(s) need to be met in order for teardown_class to be called?

I tried to follow the relevant code in pytest and pytest-xdist, but don't yet understand either sufficiently to answer this question myself.

[vitaly-krugl]

I think I figured it out. pytest_runtest_protocol() uses the nextitem parameter to determine the cleanup fixtures to call after the current item finishes executing.