pytest-logger

Pytest-logger is a pytest plugin configuring handlers for loggers from Python logging module.

You can install pytest-logger via pip from PyPI:

$ [sudo] pip install pytest-logger

Plugin puts logs on per-logger basis to:

• standard output,
• files within log-specific directory under pytest's tmpdir_factory session directory.

You can setup plugin using hook:

#conftest.py
import os

def pytest_logger_config(logger_config):
    logger_config.add_loggers(['foo', 'bar', 'baz'], stdout_level='info')
    logger_config.set_log_option_default('foo,bar')

def pytest_logger_logdirlink(config):
    return os.path.join(os.path.dirname(__file__), 'mylogs')

have logging tests or libraries (including fixtures):

#test_something.py
import pytest
import logging

foo = logging.getLogger('foo')
bar = logging.getLogger('bar')
baz = logging.getLogger('baz')

@pytest.yield_fixture(scope='session')
def session_thing():
    foo.debug('constructing session thing')
    yield
    foo.debug('destroying session thing')

@pytest.yield_fixture
def testcase_thing():
    foo.debug('constructing testcase thing')
    yield
    foo.debug('destroying testcase thing')

def test_one(session_thing, testcase_thing):
    foo.info('one executes')
    bar.warning('this test does nothing aside from logging')
    baz.info('extra log, rarely read')

def test_two(session_thing, testcase_thing):
    foo.info('two executes')
    bar.warning('neither does this')
    baz.info('extra log, not enabled by default')

and expect output in terminal (if not captured):

$ py.test -s -v
(...)
test_something.py::test_one
00:00.002 inf foo: one executes
00:00.002 wrn bar: this test does nothing aside from logging
PASSED

test_something.py::test_two
00:00.000 inf foo: two executes
00:00.000 wrn bar: neither does this
PASSED

being able to change this output by cmdline option:

$ pytest -s -v --log foo.debug,baz
(...)
test_something.py::test_one
00:00.002 dbg foo: constructing session thing
00:00.002 dbg foo: constructing testcase thing
00:00.002 inf foo: one executes
00:00.003 inf baz: extra log, rarely read
PASSED

test_something.py::test_two
00:00.000 dbg foo: constructing testcase thing
00:00.000 inf foo: two executes
00:00.001 inf baz: extra log, not enabled by default
PASSED

and - the same - in filesystem:

$ file mylogs
mylogs: symbolic link to `/tmp/pytest-of-aurzenligl/pytest-48/logs'

$ tree mylogs
mylogs
`-- test_something.py
    |-- test_one
    |   |-- bar
    |   |-- baz
    |   `-- foo
    `-- test_two
        |-- bar
        |-- baz
        `-- foo

Distributed under the terms of the MIT license, pytest-logger is free and open source software.