Mastering Python Second Edition Release Code

2022-05-05 18:25:55 +02:00
commit 3223a43fe3
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@@ -0,0 +1,4 @@
+Chapter 10, Testing and Logging
+##############################################################################
+
+| Preparing for Bugs explains how code can be tested and how logging can be added to enable easy debugging in the case of bugs at a later time.
@@ -0,0 +1,34 @@
+def square(n: int) -> int:
+    '''
+    Returns the input number, squared
+
+    >>> square(0)
+    0
+    >>> square(1)
+    1
+    >>> square(2)
+    4
+    >>> square(3)
+    9
+    >>> square()
+    Traceback (most recent call last):
+    ...
+    TypeError: square() missing 1 required positional argument: 'n'
+    >>> square('x')
+    Traceback (most recent call last):
+    ...
+    TypeError: can't multiply sequence by non-int of type 'str'
+
+    Args:
+        n (int): The number to square
+
+    Returns:
+        int: The squared result
+    '''
+    return n * n
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+
@@ -0,0 +1,14 @@
+def square(n: int) -> int:
+    '''
+    >>> square('x')
+    Traceback (most recent call last):
+        ...
+    TypeError: unsupported operand type(s) for ** or pow(): ...
+    '''
+    return n ** 2
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod(optionflags=doctest.ELLIPSIS)
+
@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
@@ -0,0 +1,61 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# This file only contains a selection of the most common options. For a full
+# list see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Path setup --------------------------------------------------------------
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#
+import os
+import sys
+sys.path.insert(0, os.path.abspath('..'))
+
+
+# -- Project information -----------------------------------------------------
+
+project = 'doctest support'
+copyright = '2020, Rick van Hattem'
+author = 'Rick van Hattem'
+
+
+# -- General configuration ---------------------------------------------------
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = [
+    'sphinx.ext.intersphinx',
+    'sphinx.ext.napoleon',
+    'sphinx.ext.autodoc',
+    'sphinx.ext.doctest',
+]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path.
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+
+
+# -- Options for HTML output -------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+#
+html_theme = 'alabaster'
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ['_static']
+
+intersphinx_mapping = {
+    'python': ('https://docs.python.org/', None),
+    'sphinx': ('https://www.sphinx-doc.org/', None),
+}
@@ -0,0 +1,21 @@
+.. doctest support documentation master file, created by
+   sphinx-quickstart on Sun Oct  4 17:57:12 2020.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Welcome to doctest support's documentation!
+===========================================
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contents:
+
+   square
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
@@ -0,0 +1,35 @@
+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=.
+set BUILDDIR=_build
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.http://sphinx-doc.org/
+	exit /b 1
+)
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+
+:end
+popd
@@ -0,0 +1,34 @@
+square module
+=============
+
+.. automodule:: square
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+Examples:
+
+.. testsetup::
+
+    from square import square
+
+.. doctest::
+
+    # pytest does not recognize testsetup
+    >>> from square import square
+    >>> square(100)
+    10000
+    >>> square(0)
+    0
+    >>> square(1)
+    1
+    >>> square(3)
+    9
+    >>> square()
+    Traceback (most recent call last):
+    ...
+    TypeError: square() missing 1 required positional argument: 'n'
+    >>> square('x')
+    Traceback (most recent call last):
+    ...
+    TypeError: can't multiply sequence by non-int of type 'str'
@@ -0,0 +1,11 @@
+'''
+>>> False
+0
+>>> True
+1
+'''
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+    doctest.testmod(optionflags=doctest.DONT_ACCEPT_TRUE_FOR_1)
@@ -0,0 +1,15 @@
+'''
+>>> [list(range(5)) for i in range(3)]
+[[0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4]]
+
+>>> # doctest: +NORMALIZE_WHITESPACE
+... [list(range(5)) for i in range(3)]
+[[0, 1, 2, 3, 4],
+ [0, 1, 2, 3, 4],
+ [0, 1, 2, 3, 4]]
+'''
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+
@@ -0,0 +1,24 @@
+'''
+>>> {10: 'a', 20: 'b'}  # doctest: +ELLIPSIS
+{...}
+>>> [True, 1, 'a']  # doctest: +ELLIPSIS
+[...]
+>>> True,  # doctest: +ELLIPSIS
+(...)
+>>> [1, 2, 3, 4]  # doctest: +ELLIPSIS
+[1, ..., 4]
+>>> [1, 0, 0, 0, 0, 0, 4]  # doctest: +ELLIPSIS
+[1, ..., 4]
+
+------------------------------------------------------------------------------
+
+>>> class Spam(object):
+...     pass
+>>> Spam()  # doctest: +ELLIPSIS
+<...Spam object at 0x...>
+'''
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+
@@ -0,0 +1,17 @@
+>>> import pprint
+
+>>> data = dict.fromkeys('spam')
+>>> pprint.pprint(data)
+{'a': None, 'm': None, 'p': None, 's': None}
+
+------------------------------------------------------------------------------
+
+>>> data = dict.fromkeys('spam')
+>>> sorted(data.items())
+[('a', None), ('m', None), ('p', None), ('s', None)]
+
+------------------------------------------------------------------------------
+
+>>> data = dict.fromkeys('spam')
+>>> data == {'a': None, 'm': None, 'p': None, 's': None}
+True
@@ -0,0 +1,11 @@
+>>> 1/3  # doctest: +ELLIPSIS
+0.333...
+>>> f'{1/3:.3f}'
+'0.333'
+>>> '{:.3f}'.format(1/3)
+'0.333'
+>>> round(1/3, 3)
+0.333
+>>> 0.333 < 1/3 < 0.334
+True
+
@@ -0,0 +1,16 @@
+>>> import time
+
+>>> a = time.time()
+>>> b = time.time()
+>>> (b - a) < 0.01
+True
+
+------------------------------------------------------------------------------
+
+>>> import datetime
+
+>>> a = datetime.datetime.now()
+>>> b = datetime.datetime.now()
+>>> str(b - a)  # doctest: +ELLIPSIS
+'0:00:00.000...
+
@@ -0,0 +1,29 @@
+import unittest
+import cube
+
+
+class TestCube(unittest.TestCase):
+
+    def test_0(self):
+        self.assertEqual(cube.cube(0), 0)
+
+    def test_1(self):
+        self.assertEqual(cube.cube(1), 1)
+
+    def test_2(self):
+        self.assertEqual(cube.cube(2), 8)
+
+    def test_3(self):
+        self.assertEqual(cube.cube(3), 27)
+
+    def test_no_arguments(self):
+        with self.assertRaises(TypeError):
+            cube.cube()
+
+    def test_exception_str(self):
+        with self.assertRaises(TypeError):
+            cube.cube('x')
+
+
+if __name__ == '__main__':
+    unittest.main()
@@ -0,0 +1,29 @@
+import unittest
+import cube
+
+n = 2
+expected = 8
+
+
+# Regular unit test
+class TestCube(unittest.TestCase):
+
+    def test_2(self):
+        self.assertEqual(cube.cube(n), expected)
+
+    def test_no_arguments(self):
+        with self.assertRaises(TypeError):
+            cube.cube()
+
+
+# py.test class
+class TestPyCube:
+
+    def test_2(self):
+        assert cube.cube(n) == expected
+
+
+# py.test functions
+def test_2():
+    assert cube.cube(n) == expected
+
@@ -0,0 +1,13 @@
+class User:
+    def __init__(self, name):
+        self.name = name
+
+    def __eq__(self, other):
+        return self.name == other.name
+
+
+def test_user_equal():
+    a = User('Rick')
+    b = User('Guido')
+
+    assert a == b
@@ -0,0 +1,13 @@
+class User:
+    def __init__(self, name):
+        self.name = name
+
+    def __eq__(self, other):
+        return self.name == other.name
+
+
+def test_user_equal():
+    a = User('Rick')
+    b = User('Guido')
+
+    assert a == b
@@ -0,0 +1,16 @@
+import pytest
+import cube
+
+
+cubes = (
+    (0, 0),
+    (1, 1),
+    (2, 8),
+    (3, 27),
+)
+
+
+@pytest.mark.parametrize('n,expected', cubes)
+def test_cube(n, expected):
+    assert cube.cube(n) == expected
+
@@ -0,0 +1,68 @@
+##################################################################
+
+import pytest
+
+
+@pytest.fixture
+def name():
+    return 'Rick'
+
+
+def test_something(name):
+    assert name == 'Rick'
+
+
+##################################################################
+
+def test_cache(cache):
+    counter = cache.get('counter', 0) + 1
+    assert counter
+    cache.set('counter', counter)
+
+##################################################################
+
+
+import pytest
+
+
+@pytest.fixture
+def some_yield_fixture():
+    with open(__file__ + '.txt', 'w') as fh:
+        # Before the function
+        yield fh
+        # After the function
+
+
+@pytest.fixture
+def some_regular_fixture():
+    # Do something here
+    return 'some_value_to_pass_as_parameter'
+
+
+def some_test(some_yield_fixture, some_regular_fixture):
+    some_yield_fixture.write(some_regular_fixture)
+
+
+##################################################################
+
+
+import pytest
+import sqlite3
+
+
+@pytest.fixture(params=[':memory:'])
+def connection(request):
+    return sqlite3.connect(request.param)
+
+
+@pytest.yield_fixture
+def transaction(connection):
+    with connection:
+        yield connection
+
+
+def test_insert(transaction):
+    transaction.execute('create table test (id integer)')
+    for i in range(3):
+        transaction.execute('insert into test values (?)', (i,))
+
@@ -0,0 +1,15 @@
+import os
+import sys
+import logging
+
+
+def test_print():
+    print('Printing to stdout')
+    print('Printing to stderr', file=sys.stderr)
+    logging.debug('Printing to debug')
+    logging.info('Printing to info')
+    logging.warning('Printing to warning')
+    logging.error('Printing to error')
+    # We don't want to display os.environ so hack around it
+    fail = 'FAIL' in os.environ
+    assert not fail
@@ -0,0 +1,16 @@
+import pytest
+import cube_root
+
+
+cubes = (
+    (0, 0),
+    (1, 1),
+    (8, 2),
+    (27, 3),
+)
+
+
+@pytest.mark.parametrize('n,expected', cubes)
+def test_cube_root(n, expected):
+    assert cube_root.cube_root(n) == expected
+
@@ -0,0 +1,21 @@
+import pytest
+import cube_root
+
+
+cubes = (
+    (0, 0),
+    (1, 1),
+    (8, 2),
+    (27, 3),
+)
+
+
+@pytest.mark.parametrize('n,expected', cubes)
+def test_cube_root(n, expected):
+    assert cube_root.cube_root(n) == expected
+
+
+def test_cube_root_below_zero():
+    with pytest.raises(ValueError):
+        cube_root.cube_root(-1)
+
@@ -0,0 +1,3 @@
+import os
+def test(a,b):
+    return c
@@ -0,0 +1,16 @@
+[pytest]
+python_files =
+    your_project_source/*.py
+    tests/*.py
+
+addopts =
+    --doctest-modules
+    --cov your_project_source
+    --cov-report term-missing
+    --cov-report html
+    --flake8
+    --mypy
+
+# W391 is the error about blank lines at the end of a file
+flake8-ignore =
+    *.py W391
@@ -0,0 +1,38 @@
+from unittest import mock
+import random
+
+
+@mock.patch('random.random')
+def test_random(mock_random):
+    # Specify our mock return value
+    mock_random.return_value = 0.1
+    # Test for the mock return value
+    assert random.random() == 0.1
+    assert mock_random.call_count == 1
+
+
+def test_random_with():
+    with mock.patch('random.random') as mock_random:
+        mock_random.return_value = 0.1
+        assert random.random() == 0.1
+
+##############################################################################
+
+
+import os
+from unittest import mock
+
+
+def delete_file(filename):
+    while os.path.exists(filename):
+        os.unlink(filename)
+
+
+@mock.patch('os.path.exists', side_effect=(True, False, False))
+@mock.patch('os.unlink')
+def test_delete_file(mock_exists, mock_unlink):
+    # First try:
+    delete_file('some non-existing file')
+
+    # Second try:
+    delete_file('some non-existing file')
@@ -0,0 +1,16 @@
+import os
+
+
+def test_chdir_monkeypatch(monkeypatch):
+    monkeypatch.chdir('/')
+    assert os.getcwd() == '/'
+
+
+def test_chdir():
+    original_directory = os.getcwd()
+    try:
+        os.chdir('/')
+        assert os.getcwd() == '/'
+    finally:
+        os.chdir(original_directory)
+
@@ -0,0 +1,4 @@
+def test_dict_merge():
+    a = dict(a=123)
+    b = dict(b=456)
+    assert a | b
@@ -0,0 +1,9 @@
+[tox]
+envlist = py3{8,9}
+skipsdist = True
+
+[testenv]
+deps =
+    pytest
+commands =
+    pytest test.py
@@ -0,0 +1,7 @@
+import logging
+
+logging.debug('debug')
+logging.info('info')
+logging.warning('warning')
+logging.error('error')
+logging.critical('critical')
@@ -0,0 +1,25 @@
+import logging
+
+log_format = (
+    '%(levelname)-8s %(name)-12s %(message)s')
+
+logging.basicConfig(
+    filename='debug.log',
+    format=log_format,
+    level=logging.DEBUG,
+)
+
+formatter = logging.Formatter(log_format)
+handler = logging.StreamHandler()
+handler.setLevel(logging.WARNING)
+handler.setFormatter(formatter)
+logging.getLogger().addHandler(handler)
+
+
+logging.debug('debug')
+logging.info('info')
+some_logger = logging.getLogger('some')
+some_logger.warning('warning')
+some_logger.error('error')
+other_logger = some_logger.getChild('other')
+other_logger.critical('critical')
@@ -0,0 +1,30 @@
+from logging import config
+
+config.dictConfig({
+    'version': 1,
+    'formatters': {
+        'standard': {
+            'format': '%(levelname)-8s %(name)-12s %(message)s',
+        },
+    },
+    'handlers': {
+        'file': {
+            'filename': 'debug.log',
+            'level': 'DEBUG',
+            'class': 'logging.FileHandler',
+            'formatter': 'standard',
+        },
+        'stream': {
+            'level': 'WARNING',
+            'class': 'logging.StreamHandler',
+            'formatter': 'standard',
+        },
+    },
+    'loggers': {
+        '': {
+            'handlers': ['file', 'stream'],
+            'level': 'DEBUG',
+        },
+    },
+})
+
@@ -0,0 +1,27 @@
+{
+    "version": 1,
+    "formatters": {
+        "standard": {
+            "format": "%(levelname)-8s %(name)-12s %(message)s"
+        }
+    },
+    "handlers": {
+        "file": {
+            "filename": "debug.log",
+            "level": "DEBUG",
+            "class": "logging.FileHandler",
+            "formatter": "standard"
+        },
+        "stream": {
+            "level": "WARNING",
+            "class": "logging.StreamHandler",
+            "formatter": "standard"
+        }
+    },
+    "loggers": {
+        "": {
+            "handlers": ["file", "stream"],
+            "level": "DEBUG"
+        }
+    }
+}
@@ -0,0 +1,12 @@
+import os
+import json
+from logging import config
+
+
+name = os.path.splitext(__file__)[0]
+json_filename = os.path.join(os.path.dirname(__file__),
+                             f'{name}.json')
+with open(json_filename) as fh:
+    config.dictConfig(json.load(fh))
+
+
@@ -0,0 +1,28 @@
+[formatters]
+keys=standard
+
+[handlers]
+keys=file,stream
+
+[loggers]
+keys=root
+
+[formatter_standard]
+format=%(levelname)-8s %(name)-12s %(message)s
+
+[handler_file]
+level=DEBUG
+class=FileHandler
+formatter=standard
+args=('debug.log',)
+
+[handler_stream]
+level=WARNING
+class=StreamHandler
+formatter=standard
+args=(sys.stderr,)
+
+[logger_root]
+handlers=file,stream
+level=DEBUG
+
@@ -0,0 +1,7 @@
+import os
+from logging import config
+
+name = os.path.splitext(__file__)[0]
+
+config.fileConfig(os.path.join(os.path.dirname(__file__),
+                  f'{name}.ini'))
@@ -0,0 +1,33 @@
+[formatters]
+keys=standard
+
+[handlers]
+keys=file,stream
+
+[loggers]
+keys=root,some
+
+[formatter_standard]
+format=%(levelname)-8s %(name)-12s %(message)s
+
+[handler_file]
+level=DEBUG
+class=FileHandler
+formatter=standard
+args=('debug.log',)
+
+[handler_stream]
+level=WARNING
+class=StreamHandler
+formatter=standard
+args=(sys.stderr,)
+
+[logger_root]
+handlers=file,stream
+level=DEBUG
+
+[logger_some]
+level=DEBUG
+qualname=some
+handlers=
+
@@ -0,0 +1,58 @@
+import sys
+
+
+def receive():
+    import time
+    import logging
+    from logging import config
+
+    listener = config.listen()
+    listener.start()
+
+    try:
+        while True:
+            logging.debug('debug')
+            logging.info('info')
+            some_logger = logging.getLogger('some')
+            some_logger.warning('warning')
+            some_logger.error('error')
+            other_logger = some_logger.getChild('other')
+            other_logger.critical('critical')
+
+            time.sleep(5)
+
+    except KeyboardInterrupt:
+        # Stop listening and finish the listening thread
+        config.stopListening()
+        listener.join()
+
+
+def send():
+    import os
+    import struct
+    import socket
+    from logging import config
+
+    ini_filename = os.path.splitext(__file__)[0] + '.ini'
+    with open(ini_filename, 'rb') as fh:
+        data = fh.read()
+
+    # Open the socket
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    # Connect to the server
+    sock.connect(('127.0.0.1', config.DEFAULT_LOGGING_CONFIG_PORT))
+    # Send the magic logging packet
+    sock.send(struct.pack('>L', len(data)))
+    # Send the config
+    sock.send(data)
+    # And close the connection again
+    sock.close()
+
+
+if __name__ == '__main__':
+    if sys.argv[-1] == 'send':
+        send()
+    elif sys.argv[-1] == 'receive':
+        receive()
+    else:
+        print(f'Usage: {sys.argv[0]} [send/receive]')
@@ -0,0 +1,35 @@
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+class MyClass(object):
+
+    def __init__(self, count):
+        self.logger = logger.getChild(self.__class__.__name__)
+
+##################################################################
+
+
+import logging
+
+logger = logging.getLogger('main_module.sub_module')
+logger.addHandler(logging.FileHandler('sub_module.log'))
+
+##################################################################
+
+
+import logging
+
+logger = logging.getLogger('main_module.sub_module')
+logger.setLevel(logging.DEBUG)
+
+##################################################################
+
+
+import logging
+
+logger = logging.getLogger()
+exception = 'Oops...'
+logger.error('Some horrible error: %r', exception)
@@ -0,0 +1,17 @@
+
+##################################################################
+
+
+import logging
+
+logger = logging.getLogger()
+logger.error('simple error', extra=dict(some_variable='my value'))
+
+##################################################################
+
+
+import logging
+
+logging.basicConfig(format='%(some_variable)s: %(message)s')
+logger = logging.getLogger()
+logger.error('the message', extra=dict(some_variable='my value'))
@@ -0,0 +1,12 @@
+import logging
+
+logging.basicConfig()
+logger = logging.getLogger()
+
+try:
+    raise RuntimeError('some runtime error')
+except Exception as exception:
+    logger.exception('Got an exception: %s', exception)
+
+logger.error('And an error')
+
@@ -0,0 +1,8 @@
+import logging
+
+
+formatter = logging.Formatter('{levelname} {message}', style='{')
+handler = logging.StreamHandler()
+handler.setFormatter(formatter)
+
+logging.error('formatted message?')
@@ -0,0 +1,23 @@
+import logging
+
+
+class FormattingMessage:
+
+    def __init__(self, message, kwargs):
+        self.message = message
+        self.kwargs = kwargs
+
+    def __str__(self):
+        return self.message.format(**self.kwargs)
+
+
+class FormattingAdapter(logging.LoggerAdapter):
+
+    def process(self, msg, kwargs):
+        msg, kwargs = super().process(msg, kwargs)
+        return FormattingMessage(msg, kwargs), dict()
+
+
+logger = FormattingAdapter(logging.root, dict())
+logger.error('Hi {name}', name='Rick')
+
@@ -0,0 +1,9 @@
+import logging
+
+
+a = logging.getLogger('a')
+ab = logging.getLogger('a.b')
+
+ab.error('before setting level')
+a.setLevel(logging.CRITICAL)
+ab.error('after setting level')
@@ -0,0 +1,13 @@
+import logging
+
+
+ab = logging.getLogger('a.b')
+ab.setLevel(logging.ERROR)
+ab.propagate = False
+ab.addHandler(logging.StreamHandler())
+
+a = logging.getLogger('a')
+
+ab.error('before setting level')
+a.setLevel(logging.CRITICAL)
+ab.error('after setting level')
@@ -0,0 +1,47 @@
+import logging
+
+
+def get_handlers(logger):
+    handlers = []
+    # Walk through the loggers and their parents recursively to
+    # fetch the handlers
+    while logger:
+        handlers += logger.handlers
+
+        if logger.propagate:
+            logger = logger.parent
+        else:
+            break
+
+    # Python has a lastResort handler in case no handlers are
+    # defined
+    if not handlers and logging.lastResort:
+        handlers.append(logging.lastResort)
+
+    return handlers
+
+
+def debug_loggers():
+    logger: logging.Logger
+    for name, logger in logging.root.manager.loggerDict.items():
+        # Placeholders are loggers without settings
+        if isinstance(logger, logging.PlaceHolder):
+            print('skipping', name)
+            continue
+
+        level = logging.getLevelName(logger.getEffectiveLevel())
+        handlers = get_handlers(logger)
+        print(f'{name}@{level}: {handlers}')
+
+
+if __name__ == '__main__':
+    a = logging.getLogger('a')
+    a.setLevel(logging.INFO)
+
+    handler = logging.StreamHandler()
+    handler.setLevel(logging.INFO)
+    ab = logging.getLogger('a.b')
+    ab.setLevel(logging.DEBUG)
+    ab.addHandler(handler)
+
+    debug_loggers()
@@ -0,0 +1,37 @@
+[report]
+# The test coverage you require, keeping to 100% is not easily
+# possible for all projects but it’s a good default for new projects.
+fail_under = 100
+
+# These functions are generally only needed for debugging and/or 
+# extra safety so we want to ignore them from the coverage 
+# requirements
+exclude_lines =
+    # Make it possible to ignore blocks of code
+    pragma: no cover
+
+    # Generally only debug code uses this
+    def __repr__
+
+    # If a debug setting is set, skip testing
+    if self\.debug:
+    if settings.DEBUG
+
+    # Don’t worry about safety checks and expected errors
+    raise AssertionError
+    raise NotImplementedError
+
+    # Do not complain about code that will never run
+    if 0:
+    if __name__ == .__main__.:
+    @abc.abstractmethod
+
+[run]
+# Make sure we require that all branches of the code is covered.
+# So both the if and the else
+branch = True
+
+# No need to require coverage of testing code
+omit =
+    test_*.py
+
@@ -0,0 +1,23 @@
+import sys
+import pathlib
+
+# Little hack to add the current directory to sys.path so we can
+# find the imports
+path = pathlib.Path(__file__).parent
+sys.path.append(str(path.resolve()))
+
+
+from T_12_assert_representation import User
+
+
+def is_user(value):
+    return isinstance(value, User)
+
+
+def pytest_assertrepr_compare(config, op, left, right):
+    if is_user(left) and is_user(right) and op == '==':
+        return [
+            'Comparing User instances:',
+            f'    name: {left.name} != {right.name}',
+        ]
+
@@ -0,0 +1,11 @@
+def cube(n: int) -> int:
+    '''
+    Returns the input number, cubed
+
+    Args:
+        n (int): The number to cube
+
+    Returns:
+        int: The cubed result
+    '''
+    return n ** 3
@@ -0,0 +1,15 @@
+def cube_root(n: int) -> int:
+    '''
+    Returns the cube root of the input number
+
+    Args:
+        n (int): The number to cube root
+
+    Returns:
+        int: The cube root result
+    '''
+    if n >= 0:
+        return n ** (1 / 3)
+    else:
+        raise ValueError('A number larger than 0 was expected')
+
@@ -0,0 +1,17 @@
+Welcome to Mastering Python's documentation!
+============================================
+
+Contents:
+
+.. toctree::
+   :maxdepth: 2
+
+   README
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
+
@@ -0,0 +1,20 @@
+def square(n: int) -> int:
+    '''
+    Returns the input number, squared
+
+    >>> square(2)
+    4
+
+    Args:
+        n (int): The number to square
+
+    Returns:
+        int: The squared result
+    '''
+    return n * n
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+