Pytester.syspathinsert() has no effect when using runpytest_subprocess() #10651
Description
Pytester.syspathinsert() uses monkeypatch to temporarily update sys.path for the length of the test. However, runpytest_subprocess() starts a new process to without any knowledge of requested changes to sys.path.
Using pytest 7.2.0, the first test case will pass, but the second will fail.
from pytest import Pytester SOME_DIR = "foobar" def test_syspathinsert__in_process__path_exists(pytester: Pytester): pytester.syspathinsert(SOME_DIR) pytester.makepyfile( f""" import sys def test_foo(): assert "{SOME_DIR}" in sys.path """ ) result = pytester.runpytest_inprocess() result.assert_outcomes(passed=1) def test_syspathinsert__sub_process__path_exists(pytester: Pytester): pytester.syspathinsert(SOME_DIR) pytester.makepyfile( f""" import sys def test_foo(): assert "{SOME_DIR}" in sys.path """ ) result = pytester.runpytest_subprocess(timeout=1) result.assert_outcomes(passed=1)