import os.path import shutil failure_demo = os.path.join(os.path.dirname(__file__), "failure_demo.py") pytest_plugins = ("pytester",) def test_failure_demo_fails_properly(pytester): target = pytester.path.joinpath(os.path.basename(failure_demo)) shutil.copy(failure_demo, target) result = pytester.runpytest(target, syspathinsert=True) result.stdout.fnmatch_lines(["*44 failed*"]) assert result.ret != 0