在并行运行pytest时只运行一次方法

 pytestrongessionfinish函数在所有测试结束时运行。如果检查worker input属性，它将在所有其他进程完成测试后在主线程中运行

def pytest_sessionfinish(session, exitstatus):
"""Insert teardown that you want to occur only once here"""
if not hasattr(session.config, "workerinput"):
pass  # whatever you want to do here

来源：https://github.com/pytest-dev/pytest-xdist/issues/271#issuecomment-826396320