Package: testtools
testtools is a set of extensions to the Python standard library’s unit testing
framework. These extensions have been derived from many years of experience
with unit testing in Python and come from many different sources.What better way to start than with a contrived code snippet?:from testtools import TestCase
from testtools.content import Content
from testtools.content_type import UTF8_TEXT
from testtools.matchers import Equals

from myproject import SillySquareServer

class TestSillySquareServer(TestCase):

    def setUp(self):
        super(TestSillySquareServer, self).setUp()
        self.server = self.useFixture(SillySquareServer())
        self.addCleanup(self.attach_log_file)

    def attach_log_file(self):
        self.addDetail(
            'log-file',
            Content(UTF8_TEXT,
                    lambda: open(self.server.logfile, 'r').readlines()))

    def test_server_is_cool(self):
        self.assertThat(self.server.temperature, Equals("cool"))

    def test_square(self):
        self.assertThat(self.server.silly_square_of(7), Equals(49))Why use testtools?Matchers: better than assertion methodsOf course, in any serious project you want to be able to have assertions that
are specific to that project and the particular problem that it is addressing.
Rather than forcing you to define your own assertion methods and maintain your
own inheritance hierarchy ofTestCaseclasses, testtools lets you write
your own “matchers”, custom predicates that can be plugged into a unit test:def test_response_has_bold(self):
   # The response has bold text.
   response = self.server.getResponse()
   self.assertThat(response, HTMLContains(Tag('bold', 'b')))More debugging info, when you need ittesttools makes it easy to add arbitrary data to your test result.  If you
want to know what’s in a log file when a test fails, or what the load was on
the computer when a test started, or what files were open, you can add that
information withTestCase.addDetail, and it will appear in the test
results if that test fails.Extend unittest, but stay compatible and re-usabletesttools goes to great lengths to allow serious test authors and testframeworkauthors to do whatever they like with their tests and their
extensions while staying compatible with the standard library’s unittest.testtools has completely parametrized how exceptions raised in tests are
mapped toTestResultmethods and how tests are actually executed (ever
wantedtearDownto be called regardless of whethersetUpsucceeds?)It also provides many simple but handy utilities, like the ability to clone a
test, aMultiTestResultobject that lets many result objects get the
results from one test suite, adapters to bring legacyTestResultobjects
into our new golden age.Cross-Python compatibilitytesttools gives you the very latest in unit testing technology in a way that
will work with Python 3.7+ and PyPy3.If you wish to use testtools with Python 2.4 or 2.5, then please use testtools
0.9.15.If you wish to use testtools with Python 2.6 or 3.2, then please use testtools
1.9.0.If you wish to use testtools with Python 3.3 or 3.4, then please use testtools 2.3.0.If you wish to use testtools with Python 2.7 or 3.5, then please use testtools 2.4.0.