pytest-catchlog

pytest-catchlog

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py.test plugin to catch log messages. This is a fork of pytest-capturelog_.

.. _pytest-capturelog: https://pypi.python.org/pypi/pytest-capturelog/

Installation

The pytest-catchlog_ package may be installed with pip or easy_install::

pip install pytest-catchlog
easy_install pytest-catchlog

.. _pytest-catchlog: http://pypi.python.org/pypi/pytest-catchlog/

Usage

If the plugin is installed log messages are captured by default and for each failed test will be shown in the same manner as captured stdout and stderr.

Running without options::

py.test test_pytest_catchlog.py

Shows failed tests like so::

----------------------- Captured stdlog call ----------------------
test_pytest_catchlog.py    26 INFO     text going to logger
----------------------- Captured stdout call ----------------------
text going to stdout
----------------------- Captured stderr call ----------------------
text going to stderr
==================== 2 failed in 0.02 seconds =====================

By default each captured log message shows the module, line number, log level and message. Showing the exact module and line number is useful for testing and debugging. If desired the log format and date format can be specified to anything that the logging module supports.

Running pytest specifying formatting options::

py.test --log-format="%(asctime)s %(levelname)s %(message)s" \
        --log-date-format="%Y-%m-%d %H:%M:%S" test_pytest_catchlog.py

Shows failed tests like so::

----------------------- Captured stdlog call ----------------------
2010-04-10 14:48:44 INFO text going to logger
----------------------- Captured stdout call ----------------------
text going to stdout
----------------------- Captured stderr call ----------------------
text going to stderr
==================== 2 failed in 0.02 seconds =====================

These options can also be customized through a configuration file::

[pytest]
log_format = %(asctime)s %(levelname)s %(message)s
log_date_format = %Y-%m-%d %H:%M:%S

Although the same effect could be achieved through the addopts setting, using dedicated options should be preferred since the latter doesn't force other developers to have pytest-catchlog installed (while at the same time, addopts approach would fail with 'unrecognized arguments' error). Command line arguments take precedence.

Further it is possible to disable reporting logs on failed tests completely with::

py.test --no-print-logs test_pytest_catchlog.py

Shows failed tests in the normal manner as no logs were captured::

----------------------- Captured stdout call ----------------------
text going to stdout
----------------------- Captured stderr call ----------------------
text going to stderr
==================== 2 failed in 0.02 seconds =====================

Inside tests it is possible to change the log level for the captured log messages. This is supported by the caplog funcarg::

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

By default the level is set on the handler used to catch the log messages, however as a convenience it is also possible to set the log level of any logger::

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

It is also possible to use a context manager to temporarily change the log level::

def test_bar(caplog):
    with caplog.at_level(logging.INFO):
        pass

Again, by default the level of the handler is affected but the level of any logger can be changed instead with::

def test_bar(caplog):
    with caplog.at_level(logging.CRITICAL, logger='root.baz'):
        pass

Lastly all the logs sent to the logger during the test run are made available on the funcarg in the form of both the LogRecord instances and the final log text. This is useful for when you want to assert on the contents of a message::

def test_baz(caplog):
    func_under_test()
    for record in caplog.records:
        assert record.levelname != 'CRITICAL'
    assert 'wally' not in caplog.text

For all the available attributes of the log records see the logging.LogRecord class.

You can also resort to record_tuples if all you want to do is to ensure, that certain messages have been logged under a given logger name with a given severity and message::

def test_foo(caplog):
    logging.getLogger().info('boo %s', 'arg')

    assert caplog.record_tuples == [
        ('root', logging.INFO, 'boo arg'),
    ]

Changelog

List of notable changes between pytest-catchlog releases.

.. %UNRELEASED_SECTION%

1.2.2_

Released on 2016-01-24 UTC.

• [Bugfix] #30_ #31_ - Fix unicode vs str compatibility issues between Python2 and Python3. (Thanks goes to @sirex_ for reporting the issue and providing a fix!)

.. _#30: https://github.com/eisensheng/pytest-catchlog/issues/30 .. _#31: https://github.com/eisensheng/pytest-catchlog/issues/31 .. _@sirex: https://github.com/sirex

1.2.1_

Released on 2015-12-07.

• [Bugfix] #18 - Allow caplog.records() to be modified. Thanks to Eldar Abusalimov for the PR and Marco Nenciarini for reporting the issue.
• [Bugfix] #15 #17 - Restore Python 2.6 compatibility. (Thanks to Marco Nenciarini!)

.. attention:: Deprecation warning: the following objects (i.e. functions, properties) are slated for removal in the next major release.

- ``caplog.at_level`` and ``caplog.set_level`` should be used instead of
  ``caplog.atLevel`` and ``caplog.setLevel``.

  The methods ``caplog.atLevel`` and ``caplog.setLevel`` are still
  available but deprecated and not supported since they don't follow
  the PEP8 convention for method names.

- ``caplog.text``, ``caplog.records`` and
  ``caplog.record_tuples`` were turned into properties.
  They still can be used as regular methods for backward compatibility,
  but that syntax is considered deprecated and scheduled for removal in
  the next major release.

Version 1.2

Released on 2015-11-08.

• [Feature] #6 - Configure logging message and date format through ini file.
• [Feature] #7 - Also catch logs from setup and teardown stages.
• [Feature] #7 - Replace deprecated __multicall__ use to support future Py.test releases.
• [Feature] #11 - reintroduce setLevel and atLevel to retain backward compatibility with pytest-capturelog. Also the members text, records and record_tuples of the caplog fixture can be used as properties now.

Special thanks for this release goes to Eldar Abusalimov. He provided all of the changed features.

Version 1.1

Released on 2015-06-07.

• #2 - Explicitly state Python3 support and add configuration for running tests with tox on multiple Python versions. (Thanks to Jeremy Bowman!)
• Add an option to silence logs completely on the terminal.

Version 1.0

Released on 2014-12-08.

• Add record_tuples for comparing recorded log entries against expected log entries with their logger name, severity and formatted message.