def test_hook_proxy(pytester: Pytester) -> None:
    """Session's gethookproxy() would cache conftests incorrectly (#2016).
    It was decided to remove the cache altogether.
    """
    pytester.makepyfile(
        **{
            "root/demo-0/test_foo1.py": "def test1(): pass",
            "root/demo-a/test_foo2.py": "def test1(): pass",
            "root/demo-a/conftest.py": """\
            def pytest_ignore_collect(collection_path, config):
                return True
            """,
            "root/demo-b/test_foo3.py": "def test1(): pass",
            "root/demo-c/test_foo4.py": "def test1(): pass",
        }
    )
    result = pytester.runpytest()
    result.stdout.fnmatch_lines(
        ["*test_foo1.py*", "*test_foo3.py*", "*test_foo4.py*", "*3 passed*"]
    )
Session's gethookproxy() would cache conftests incorrectly (#2016).
    It was decided to remove the cache altogether.
    
testing/test_conftest.py