pytest 3.0.0+ and python-ldap

[aoodham]

Hi,

We've noticed an issue when using py.test on modules which have a dependency on python-ldap.
The stack trace is:

09:45:24 /usr/lib/python2.7/site-packages/py/_path/common.py:332: in visit
09:45:24     for x in Visitor(fil, rec, ignore, bf, sort).gen(self):
09:45:24 /usr/lib/python2.7/site-packages/py/_path/common.py:368: in gen
09:45:24     if p.check(dir=1) and (rec is None or rec(p))])
09:45:24 /usr/lib/python2.7/site-packages/_pytest/main.py:672: in _recurse
09:45:24     ihook = self.gethookproxy(path)
09:45:24 /usr/lib/python2.7/site-packages/_pytest/main.py:575: in gethookproxy
09:45:24     my_conftestmodules = pm._getconftestmodules(fspath)
09:45:24 /usr/lib/python2.7/site-packages/_pytest/config.py:315: in _getconftestmodules
09:45:24     mod = self._importconftest(conftestpath)
09:45:24 /usr/lib/python2.7/site-packages/_pytest/config.py:340: in _importconftest
09:45:24     raise ConftestImportFailure(conftestpath, sys.exc_info())
09:45:24 E   ConftestImportFailure: SyntaxError('invalid syntax', ('<string>', 1, 1, '@py_builtins'))
09:45:24 E     File "/usr/lib/python2.7/site-packages/_pytest/assertion/rewrite.py", line 207, in load_module
09:45:24 E       py.builtin.exec_(co, mod.__dict__)
09:45:24 E     File "/usr/lib/python2.7/site-packages/py/_builtin.py", line 221, in exec_
09:45:24 E       exec2(obj, globals, locals)
09:45:24 E     File "<string>", line 7, in exec2
09:45:24 E     File "/home/jenkins/workspace/cloud-explorer/software/nexus/cloud_explorer/python/sl/test_explorer/explorer_unit_test/conftest.py", line 6, in <module>
09:45:24 E       from sl.explorer import upgrade
09:45:24 E     File "/usr/lib/python2.7/site-packages/_pytest/assertion/rewrite.py", line 207, in load_module
09:45:24 E       py.builtin.exec_(co, mod.__dict__)
09:45:24 E     File "/usr/lib/python2.7/site-packages/py/_builtin.py", line 221, in exec_
09:45:24 E       exec2(obj, globals, locals)
09:45:24 E     File "<string>", line 7, in exec2
09:45:24 E     File "/home/jenkins/workspace/cloud-explorer/software/nexus/cloud_explorer/python/sl/explorer/upgrade.py", line 9, in <module>
09:45:24 E       import ldap
09:45:24 E     File "/usr/lib64/python2.7/site-packages/ldap/__init__.py", line 85, in <module>
09:45:24 E       from functions import open,initialize,init,get_option,set_option,escape_str
09:45:24 E     File "/usr/lib/python2.7/site-packages/_pytest/assertion/rewrite.py", line 207, in load_module
09:45:24 E       py.builtin.exec_(co, mod.__dict__)
09:45:24 E     File "/usr/lib/python2.7/site-packages/py/_builtin.py", line 221, in exec_
09:45:24 E       exec2(obj, globals, locals)
09:45:24 E     File "<string>", line 7, in exec2
09:45:24 E     File "/usr/lib64/python2.7/site-packages/ldap/functions.py", line 36, in <module>
09:45:24 E       from ldap.ldapobject import LDAPObject
09:45:24 E     File "/usr/lib/python2.7/site-packages/_pytest/assertion/rewrite.py", line 207, in load_module
09:45:24 E       py.builtin.exec_(co, mod.__dict__)
09:45:24 E     File "/usr/lib/python2.7/site-packages/py/_builtin.py", line 221, in exec_
09:45:24 E       exec2(obj, globals, locals)
09:45:24 E     File "<string>", line 7, in exec2
09:45:24 E     File "/usr/lib64/python2.7/site-packages/ldap/ldapobject.py", line 37, in <module>
09:45:24 E       from ldap.schema import SCHEMA_ATTRS
09:45:24 E     File "/usr/lib64/python2.7/site-packages/ldap/schema/__init__.py", line 11, in <module>
09:45:24 E       from ldap.schema.subentry import SubSchema,SCHEMA_ATTRS,SCHEMA_CLASS_MAPPING,SCHEMA_ATTR_MAPPING,urlfetch
09:45:24 E     File "/usr/lib/python2.7/site-packages/_pytest/assertion/rewrite.py", line 207, in load_module
09:45:24 E       py.builtin.exec_(co, mod.__dict__)
09:45:24 E     File "/usr/lib/python2.7/site-packages/py/_builtin.py", line 221, in exec_
09:45:24 E       exec2(obj, globals, locals)
09:45:24 E     File "<string>", line 7, in exec2
09:45:24 E     File "/usr/lib64/python2.7/site-packages/ldap/schema/subentry.py", line 19, in <module>
09:45:24 E       o = eval(_name)

This is running on a Fedora 20 machine with py.test 3.0.1 and python-ldap version 2.4.17. Although I can repeat the same on a fedora 23 machine running py.test 3.0.1/ 3.0.0 and python ldap 2.4.17/27
I can't seem to recreate this with a simple minimal example. Just having a test which references a conftest which imports ldap doesn't seem to work - so something strange must be happening, but I don't know what else to try.

---

(edited by @The-Compiler to add code symbols around the stacktrace)

[The-Compiler]

I'm guessing this is somehow caused by #1619, because assertion rewriting wasn't done in conftest.py before - cc @flub @nicoddemus @sober7

Any chance you can share the full conftest.py where this happens?

[aoodham]

Sure, the conftest file contains:

from flask_mako import render_template
from mock import Mock
import pytest

from sl.explorer import upgrade

from sl.explorer.models import Task, PbxPatch

@pytest.fixture()
def single_patch_db(app):

    db = app.extensions['sqlalchemy'].db
    with app.app_context():
        Task.query.delete(synchronize_session=False)
        PbxPatch.schedule(session=db.session,
                          patchFile='Test_patch_file',
                          patchVersion='1.8.2rc7',
                          endStep='Live',
                          )
        db.session.commit()

    return db


@pytest.fixture()
def single_archive_patch_db(app):

    db = app.extensions['sqlalchemy'].db
    with app.app_context():
        Task.query.delete(False)
        PbxPatch.schedule(session=db.session,
                          patchFile='Test_patch_file',
                          patchVersion='1.8.3d6',
                          endStep='Live',
                          active=False
        )
        db.session.commit()

    return db

@pytest.fixture
def render_template_spy(monkeypatch):
    render_template_spy = Mock(wraps=render_template)
    monkeypatch.setattr(upgrade, 'render_template', render_template_spy)
    return render_template_spy

This is the one which has the import which references ldap. There is another conftest file higher up the tree, which in turn uses the pytest_plugins keyword to pull in an additional file.

I can share those as well, if the above isn't of much help

[The-Compiler]

So from what I see from that stacktrace, there are two relevant things happening here:

• ldap/schema/subentry.py has this interesting snippet:

18  for _name in dir():
19    o = eval(_name)
20    if hasattr(o,'schema_attribute'):
21      SCHEMA_CLASS_MAPPING[o.schema_attribute] = o
22      SCHEMA_ATTR_MAPPING[o] = o.schema_attribute

• pytest seems to insert its @py_builtins global into that module, which causes that eval to fail.

I wonder, why is 2) happening? Do you use pytest.register_assert_rewrite somewhere?

[nicoddemus]

A bug was fixed just yesterday related to pytest_plugins defined as a string (as opposed to a list[str]) marking a lot of modules for assertion rewriting when they shouldn't be rewritten.

@aoodham Is it possible to test using the latest master and see if it has fixed this issue as well?

[aoodham]

@nicoddemus:

Just tried running the test suite with latest master - it all looks good:

============================================================================================================ test session starts =============================================================================================================
platform linux2 -- Python 2.7.11, pytest-3.0.2.dev, py-1.4.31, pluggy-0.3.1 -- /bin/python
cachedir: .cache
rootdir: /home/apw/software, inifile: 
collected 132 items 
<all tests pass, not going to print it here, mostly boring>
=========================================================================================================== pytest-warning summary ===========================================================================================================
WP1 None Modules are already imported so can not be re-written: sl.nexustest.db_plugin
============================================================================================================ 39 tests deselected =============================================================================================================
======================================================================================== 93 passed, 39 deselected, 1 pytest-warnings in 20.65 seconds ========================================================================================

So aside from the warning - which I'm guessing didn't stop anything from happening, it all looks fine

[nicoddemus]

Great! 😁

That warning only means that sl.nexustest.db_plugin was already imported by the time pytest start rewriting assertion in test modules. If you have plain asserts in that module, I suggest you call pytest.register_assertion_rewrite at some point before it gets imported (possibly right before/after the pytest_plugins declaration).

I'm closing this for now then.