UnicodeEncodeError in warnings capture

[coldnight]

• Include a detailed description of the bug or suggestion
  We run tests in a CI server, but somethings it failed because the below internal error:

INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/main.py", line 105, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/main.py", line 141, in _main
INTERNALERROR>     config.hook.pytest_runtestloop(session=session)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 745, in __call__
INTERNALERROR>     return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 339, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 334, in <lambda>
INTERNALERROR>     _MultiCall(methods, kwargs, hook.spec_opts).execute()
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 613, in execute
INTERNALERROR>     return _wrapped_call(hook_impl.function(*args), self.execute)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 250, in _wrapped_call
INTERNALERROR>     wrap_controller.send(call_outcome)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 280, in get_result
INTERNALERROR>     _reraise(*ex)  # noqa
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 265, in __init__
INTERNALERROR>     self.result = func()
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 614, in execute
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/main.py", line 164, in pytest_runtestloop
INTERNALERROR>     item.config.hook.pytest_runtest_protocol(item=item, nextitem=nextitem)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 745, in __call__
INTERNALERROR>     return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 339, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 334, in <lambda>
INTERNALERROR>     _MultiCall(methods, kwargs, hook.spec_opts).execute()
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 613, in execute
INTERNALERROR>     return _wrapped_call(hook_impl.function(*args), self.execute)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 250, in _wrapped_call
INTERNALERROR>     wrap_controller.send(call_outcome)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/warnings.py", line 73, in pytest_runtest_protocol
INTERNALERROR>     yield
INTERNALERROR>   File "/usr/local/lib/python2.7/contextlib.py", line 24, in __exit__
INTERNALERROR>     self.gen.next()
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/_pytest/warnings.py", line 66, in catch_warnings_for_item
INTERNALERROR>     warning.filename, warning.lineno, warning.line)
INTERNALERROR>   File "/buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/warnings.py", line 50, in formatwarning
INTERNALERROR>     s =  "%s: %s: %s\n" % (lineno, category.__name__, message)
INTERNALERROR> UnicodeEncodeError: 'ascii' codec can't encode characters in position 35-37: ordinal not in range(128)

This problem is weird, sometimes happened and sometimes not. So I don't know why, and I can't let it happened again manually.

• pip list of the virtual environment you are using

amqp (2.1.4)
appdirs (1.4.3)
backports-abc (0.5)
better-exceptions (0.1.8)
billiard (3.5.0.2)
celery (4.0.2)
certifi (2017.4.17)
common (2.4.8)
contextlib2 (0.5.5)
coverage (4.4.1)
decorator (4.0.11)
enum34 (1.1.6)
funcsigs (1.0.2)
gredis (0.0.8)
hashids (1.2.0)
Jinja2 (2.9.6)
kombu (4.0.2)
MarkupSafe (1.0)
mock (2.0.0)
modcov (0.0.3.dev30)
MySQL-python (1.2.5)
olefile (0.44)
packaging (16.8)
pbr (3.0.1)
Pillow (4.1.1)
pip (9.0.1)
py (1.4.33)
py-dateutil (2.2)
pycrypto (2.6.1)
pycurl (7.43.0)
pyparsing (2.2.0)
pytest (3.1.0)
pytest-cov (2.5.1)
pytz (2017.2)
qrcode (5.3)
raven (6.0.0)
redis (2.10.5)
requests (2.14.2)
setuptools (35.0.2)
singledispatch (3.4.0.3)
six (1.10.0)
SQLAlchemy (1.1.10)
sqlalchemy-migrate (0.11.0)
sqlparse (0.2.3)
suds-jurko (0.6)
Tempita (0.5.2)
tornado (4.5.1)
vine (1.1.3)
wheel (0.29.0)
wheezy.captcha (0.1.44)
xlrd (1.0.0)
xlwt (1.2.0)

• pytest and operating system versions

$ .tox/py27/bin/pytest --version
This is pytest version 3.1.0, imported from /buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/pytest.pyc
setuptools registered plugins:
  pytest-cov-2.5.1 at /buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/pytest_cov/plugin.py
  celery-4.0.2 at /buildbot/worker/agent-admin_auto-test/build/.tox/py27/lib/python2.7/site-packages/celery/contrib/pytest.py

$ uname -a
Linux d4ad8bbd6105 4.4.0-78-generic #99-Ubuntu SMP Thu Apr 27 15:29:09 UTC 2017 x86_64 GNU/Linux

• Minimal example if possible

[coldnight]

It seems like this problem caused by MySQLdb's warnings, check this out: https://stackoverflow.com/questions/19806219/unicodeencodeerror-when-mysqldb-show-warnings. I will try to ignore those warnings to figure out this problem.

[coldnight]

# -*- coding:utf-8 -*-

import warnings


def test_ok():
    warnings.warn(u"测试")

Save the code to test.py and then run command below:

$ pytest test.py

[RonnyPfannschmidt]

my understanding is that python warnings supports only strings, so passing it unicode on python2 is breaking it,

im not sure if and how pytest should work around a "broken" stdlib

[coldnight]

@RonnyPfannschmidt Hi, I have made a PR try to fix this, please see #2437