py.test日志控制

Question

We have recently switched to py.test for python testing (which is fantastic btw). However, I'm trying to figure out how to control the log output (ie the built-in python logging module). We have pytest-capturelog installed and this works as expected and when we want to see logs we can pass --nologcapture option.

However, how do you control the logging level (eg info, debug etc.) and also filter the logging (if you're only interested in a specific module). Is there existing plugins for py.test to achieve this or do we need to roll our own?

Thanks, Jonny

Answer 1

Installing and using the pytest-capturelog plugin could satisfy most of your pytest/logging needs. If something is missing you should be able to implement it relatively easily.

Answer 2

As Holger said you can use pytest-capturelog :

def test_foo(caplog):
    caplog.setLevel(logging.INFO)
    pass

If you don't want to use pytest-capturelog you can use a stdout StreamHandler in your logging config so pytest will capture the log output. Here is an example basicConfig

logging.basicConfig(level=logging.DEBUG, stream=sys.stdout)

Answer 3

A bit of a late contribution, but I can recommend pytest-logging for a simple drop-in logging capture solution. After pip install pytest-logging you can control the verbosity of the your logs (displayed on screen) with

$ py.test -s -v tests/your_test.py
$ py.test -s -vv tests/your_test.py
$ py.test -s -vvvv tests/your_test.py

etc... NB - the -s flag is important, without it py.test will filter out all the sys.stderr information.

Answer 4

Pytest now has native support for logging control via the caplog fixture; no need for plugins.

You can specify the logging level for a particular logger or by default for the root logger:

import pytest

def test_bar(caplog):
    caplog.set_level(logging.CRITICAL, logger='root.baz')

Pytest also captures log output in caplog.records so you can assert logged levels and messages. For further information see the official documentation here and here .

Answer 5

A bit of an even later contribution: you can try pytest-logger . Novelty of this plugin is logging to filesystem: pytest provides nodeid for each test item, which can be used to organize test session logs directory (with help of pytest tmpdir facility and it's testcase begin/end hooks).

You can configure multiple handlers (with levels) for terminal and filesystem separately and provide own cmdline options for filtering loggers/levels to make it work for your specific test environment - eg by default you can log all to filesystem and small fraction to terminal, which can be changed on per-session basis with --log option if needed. Plugin does nothing by default, if user defines no hooks.