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From: Facundo Batista <facundobatista@gmail.com>
Newsgroups: comp.lang.python.announce
Subject: Released logassert 5
Date: Thu, 6 Aug 2020 14:16:02 -0300
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I'm happy to bring you a new release of logassert, a simple logging
assertion mechanism for Python unittests.

Because we all know that we must test the logging calls in our
programs, right? With `logassert` this is very easy.

This new release brings the functionality of logassert as a pytest
fixture, with totally renewed semantics (for "classic unittest"
structures, logassert is not changing much, to be backwards
compatibile).

So, for pytest all you need to do is to declare `logs` in your test
arguments (it works just like any other fixture), and then just check
(using `assert`, as usual with *pytest*) if a specific
line is in the logs for a specific level.

See this example, with several log lines, and a specific assertion:

    logger.info("Starting system")
    places = ['/tmp/', '~/temp']
    logger.debug("Checking for config XYZ in all these places %s", places)
    logger.warning("bad config XYZ")

    assert "bad config XYZ" in logs.debug

See how the test failure message is super helpful:

assert for regex 'bad config XYZ' check in DEBUG, failed; logged lines:
       INFO      'Starting system'
       DEBUG     "Checking for config XYZ in all these places
['/tmp/', '~/temp']"
       WARNING   'bad config XYZ'

You can install logassert from PyPI:

    https://pypi.org/project/logassert/

The project is in Github:

    https://github.com/facundobatista/logassert

Interested on more detail about how this work?

As I said above, you include the `logs` fixture and just assert.  Example:

    def test_bleh(logs)
        (...)
        assert "The meaning of life is 42" in logs.debug

Actually, the line you write is a regular expression, so you can
totally do (in case you're not exactly sure which the meaning of life
is):

    assert "The meaning of life is \d+" in logs.debug

The indicated string is searched to be inside the log lines, it
doesn't need to be exact whole line. If you want that, just indicate
it as with any regular expression:

    assert "^The meaning of life is \d+$" in logs.debug

In a similar way you can also express the desire to check if it's at
the beginning or at the end of the log lines.

**NOTE**: the message checked is the final one, after the logging
system replaced all the indicated parameters in the indicated string.

If you want to verify that a text was logged, no matter at which level, just do:

    assert "The meaning of life is 42" in logs.any_level

To verify that some text was NOT logged, just juse the Python's
syntax!  For example:

    assert "A problem happened" not in logs.error

If you don't like regexes just import `Exact` from `logassert` and
wrap the string
with that. For example, in this case the `..` means exactly two dots, no regex
semantics at all:

    assert Exact("The meaning of life is ..") in logs.any_level

If you need help, or have any question, or found any issue, please open a
ticket [here](https://github.com/facundobatista/logassert/issues/new).

Thanks in advance for your time.

-- 
.    Facundo

Blog: http://www.taniquetil.com.ar/plog/
PyAr: http://www.python.org.ar/
Twitter: @facundobatista