monkeypatching PYTHONPATH breaks real PYTHONPATH #4913
Description
In Fedora, we invoke tests with custom PATH and PYTHONPATH set:
PATH=%{buildroot}%{_bindir}:${PATH} \
PYTHONPATH=%{buildroot}%{python2_sitelib} \
%{buildroot}%{_bindir}/pytest-%{python2_version} -r s testing
PATH=%{buildroot}%{_bindir}:${PATH} \
PYTHONPATH=%{buildroot}%{python3_sitelib} \
%{buildroot}%{_bindir}/pytest-%{python3_version} -r s testing
The monkeypatching in
pytest/testing/test_collection.py
Line 1111 in 51bf7c3
breaks that:
=================================== FAILURES ===================================
______________________ test_collect_pyargs_with_testpaths ______________________
testdir = <Testdir local('/tmp/pytest-of-mockbuild/pytest-0/test_collect_pyargs_with_testpaths0')>
monkeypatch = <_pytest.monkeypatch.MonkeyPatch object at 0x7f9018546b50>
def test_collect_pyargs_with_testpaths(testdir, monkeypatch):
testmod = testdir.mkdir("testmod")
# NOTE: __init__.py is not collected since it does not match python_files.
testmod.ensure("__init__.py").write("def test_func(): pass")
testmod.ensure("test_file.py").write("def test_func(): pass")
root = testdir.mkdir("root")
root.ensure("pytest.ini").write(
textwrap.dedent(
"""
[pytest]
addopts = --pyargs
testpaths = testmod
"""
)
)
monkeypatch.setenv("PYTHONPATH", str(testdir.tmpdir))
with root.as_cwd():
result = testdir.runpytest_subprocess()
> result.stdout.fnmatch_lines(["*1 passed in*"])
E Failed: remains unmatched: '*1 passed in*'
/builddir/build/BUILD/pytest-4.3.0/testing/test_collection.py:1114: Failed
----------------------------- Captured stdout call -----------------------------
running: /usr/bin/python2 -mpytest --basetemp=/tmp/pytest-of-mockbuild/pytest-0/test_collect_pyargs_with_testpaths0/runpytest-0
in: /tmp/pytest-of-mockbuild/pytest-0/test_collect_pyargs_with_testpaths0/root
----------------------------- Captured stderr call -----------------------------
/usr/bin/python2: No module named pytest
=============================== warnings summary ===============================
testing/test_warnings.py::test_group_warnings_by_message
I think the fix is to read PYTHONPATH and only prepend the patched value.
Will try to see if it helps.