Scopes of fixtures:
- Function (default): The setup/teardown runs before/after every run of the test function or fixture that depends on it
- Class: The setup/teardown runs before/after once for all the test methods inside a class
- Module: The setup/teardown runs before/after once for all the test functions/methods inside a module
- Package: The setup/teardown runs before/after once for all the test functions/methods inside a package or test directory
- Session: The setup/teardown runs before/after once for all the test functions/methods per session
A fixture can only depend on another fixture that is at the same scope level or wider. Also, for package/session scopes, the fixtures have to be defined inside conftest.py (typically in the root of test directory) that will be read by pytest before running tests in order to be actually at the package/session level; otherwise, they will default to the module.