diff --git a/setup.py b/setup.py
index 36e5ee5..c93d8f5 100644
--- a/setup.py
+++ b/setup.py
@@ -28,7 +28,7 @@
 
 EXTRAS_REQUIRE = {
     'test': TESTS_REQUIRE,
-    #':sys_platform == "win32"': ['pywin32'],
+    # ':sys_platform == "win32"': ['pywin32'],
     # Because https://sourceforge.net/p/pywin32/bugs/680/
     ':sys_platform == "win32"': ['pypiwin32'],
     'docs': [
@@ -50,55 +50,56 @@ def read(*rnames):
     read('CHANGES.rst')
 )
 
-setup(name='zope.sendmail',
-      version='4.2.2.dev0',
-      url='https://github.com/zopefoundation/zope.sendmail',
-      license='ZPL 2.1',
-      description='Zope sendmail',
-      author='Zope Foundation and Contributors',
-      author_email='zope-dev@zope.org',
-      long_description=LONG_DESCRIPTION,
-      classifiers=[
-          'Development Status :: 5 - Production/Stable',
-          'Environment :: Web Environment',
-          'Intended Audience :: Developers',
-          'License :: OSI Approved :: Zope Public License',
-          'Programming Language :: Python',
-          'Programming Language :: Python :: 2',
-          'Programming Language :: Python :: 2.7',
-          'Programming Language :: Python :: 3',
-          'Programming Language :: Python :: 3.4',
-          'Programming Language :: Python :: 3.5',
-          'Programming Language :: Python :: 3.6',
-          'Programming Language :: Python :: 3.7',
-          'Programming Language :: Python :: Implementation :: CPython',
-          'Programming Language :: Python :: Implementation :: PyPy',
-          'Operating System :: OS Independent',
-          'Topic :: Internet :: WWW/HTTP',
-          'Topic :: Communications :: Email',
-          'Framework :: Zope :: 3',
-      ],
-      packages=find_packages('src'),
-      package_dir={'': 'src'},
-      namespace_packages=['zope'],
-      extras_require=EXTRAS_REQUIRE,
-      install_requires=[
-          'setuptools',
-          'transaction',
-          'zope.i18nmessageid',
-          'zope.interface',
-          'zope.schema',
-          # it's only needed for vocabulary, zcml and tests
-          'zope.component>=3.8.0',
-          # these are only needed for zcml
-          'zope.configuration',
-      ],
-      tests_require=TESTS_REQUIRE,
-      test_suite='zope.sendmail.tests',
-      include_package_data=True,
-      zip_safe=False,
-      entry_points="""
+setup(
+    name='zope.sendmail',
+    version='4.2.2.dev0',
+    url='https://github.com/zopefoundation/zope.sendmail',
+    license='ZPL 2.1',
+    description='Zope sendmail',
+    author='Zope Foundation and Contributors',
+    author_email='zope-dev@zope.org',
+    long_description=LONG_DESCRIPTION,
+    classifiers=[
+        'Development Status :: 5 - Production/Stable',
+        'Environment :: Web Environment',
+        'Intended Audience :: Developers',
+        'License :: OSI Approved :: Zope Public License',
+        'Programming Language :: Python',
+        'Programming Language :: Python :: 2',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: Implementation :: CPython',
+        'Programming Language :: Python :: Implementation :: PyPy',
+        'Operating System :: OS Independent',
+        'Topic :: Internet :: WWW/HTTP',
+        'Topic :: Communications :: Email',
+        'Framework :: Zope :: 3',
+    ],
+    packages=find_packages('src'),
+    package_dir={'': 'src'},
+    namespace_packages=['zope'],
+    extras_require=EXTRAS_REQUIRE,
+    install_requires=[
+        'setuptools',
+        'transaction',
+        'zope.i18nmessageid',
+        'zope.interface',
+        'zope.schema',
+        # it's only needed for vocabulary, zcml and tests
+        'zope.component>=3.8.0',
+        # these are only needed for zcml
+        'zope.configuration',
+    ],
+    tests_require=TESTS_REQUIRE,
+    test_suite='zope.sendmail.tests',
+    include_package_data=True,
+    zip_safe=False,
+    entry_points="""
       [console_scripts]
       zope-sendmail = zope.sendmail.queue:run
-      """
+    """
 )
diff --git a/src/zope/__init__.py b/src/zope/__init__.py
index 2cdb0e4..656dc0f 100644
--- a/src/zope/__init__.py
+++ b/src/zope/__init__.py
@@ -1 +1 @@
-__import__('pkg_resources').declare_namespace(__name__) # pragma: no cover
+__import__('pkg_resources').declare_namespace(__name__)  # pragma: no cover
diff --git a/src/zope/sendmail/delivery.py b/src/zope/sendmail/delivery.py
index 5f4d8ce..c7b7b7b 100644
--- a/src/zope/sendmail/delivery.py
+++ b/src/zope/sendmail/delivery.py
@@ -34,10 +34,12 @@
 
 # BBB: this import is needed for backward compatibility with older versions of
 # zope.sendmail which defined QueueProcessorThread in this module
-from zope.sendmail.queue import QueueProcessorThread
+from zope.sendmail.queue import QueueProcessorThread  # noqa: F401
+
 
 log = logging.getLogger("MailDataManager")
 
+
 @implementer(IDataManager)
 class MailDataManager(object):
 
@@ -80,7 +82,7 @@ def tpc_vote(self, txn):
     def tpc_finish(self, txn):
         try:
             self.callable(*self.args)
-        except Exception as e:
+        except Exception:
             # Any exceptions here can cause database corruption.
             # Better to protect the data and potentially miss emails than
             # leave a database in an inconsistent state which requires a
diff --git a/src/zope/sendmail/interfaces.py b/src/zope/sendmail/interfaces.py
index 4cfbf51..14fa1a6 100644
--- a/src/zope/sendmail/interfaces.py
+++ b/src/zope/sendmail/interfaces.py
@@ -112,7 +112,7 @@ class IMailQueueProcessor(Interface):
     pollingInterval = Int(
         title=_(u"Polling Interval"),
         description=_(u"How often the queue is checked for new messages"
-                       " (in milliseconds)"),
+                      u" (in milliseconds)"),
         default=5000)
 
     mailer = Attribute("IMailer that is used for message delivery")
@@ -134,12 +134,12 @@ def send(fromaddr, toaddrs, message):
 
         Messages are sent immediately.
         """
-    
+
     def abort():
         """Abort sending the message for asynchronous subclasses."""
-    
+
     def vote(fromaddr, toaddrs, message):
-        """Raise an exception if there is a known reason why the message 
+        """Raise an exception if there is a known reason why the message
         cannot be sent."""
 
 
@@ -253,4 +253,3 @@ def abort():
 
         Calling ``abort()`` more than once is allowed.
         """
-
diff --git a/src/zope/sendmail/maildir.py b/src/zope/sendmail/maildir.py
index 918378f..bd3d8c6 100644
--- a/src/zope/sendmail/maildir.py
+++ b/src/zope/sendmail/maildir.py
@@ -25,6 +25,7 @@
      IMaildirFactory, IMaildir, IMaildirMessageWriter
 from zope.sendmail._compat import text_type
 
+
 @provider(IMaildirFactory)
 @implementer(IMaildir)
 class Maildir(object):
@@ -91,7 +92,8 @@ def newMessage(self):
                                       random.randrange(randmax))
             filename = join(subdir_tmp, unique)
             try:
-                fd = os.open(filename, os.O_CREAT|os.O_EXCL|os.O_WRONLY, 0o600)
+                fd = os.open(filename, os.O_CREAT | os.O_EXCL | os.O_WRONLY,
+                             0o600)
             except OSError as e:
                 if e.errno != errno.EEXIST:
                     raise
@@ -119,7 +121,6 @@ def _encode_utf8(s):
 class MaildirMessageWriter(object):
     """See :class:`zope.sendmail.interfaces.IMaildirMessageWriter`"""
 
-
     def __init__(self, fd, filename, new_filename):
         self._filename = filename
         self._new_filename = new_filename
diff --git a/src/zope/sendmail/mailer.py b/src/zope/sendmail/mailer.py
index 6d14d34..36ed96d 100644
--- a/src/zope/sendmail/mailer.py
+++ b/src/zope/sendmail/mailer.py
@@ -31,6 +31,7 @@ class _SMTPState(local):
     code = None
     response = None
 
+
 @implementer(ISMTPMailer)
 class SMTPMailer(object):
     """Implementation of :class:`zope.sendmail.interfaces.ISMTPMailer`."""
@@ -107,8 +108,8 @@ def send(self, fromaddr, toaddrs, message):
                     password = password.encode('utf-8')
                 connection.login(username, password)
         elif self.username:
-            raise RuntimeError('Mailhost does not support ESMTP but a username '
-                               'is configured')
+            raise RuntimeError(
+                'Mailhost does not support ESMTP but a username is configured')
 
         try:
             connection.sendmail(fromaddr, toaddrs, message)
diff --git a/src/zope/sendmail/queue.py b/src/zope/sendmail/queue.py
index 2f21a24..9d0f8c4 100644
--- a/src/zope/sendmail/queue.py
+++ b/src/zope/sendmail/queue.py
@@ -22,7 +22,6 @@
 import argparse
 import os
 import smtplib
-import stat
 import threading
 import time
 import errno
@@ -31,9 +30,11 @@
 from zope.sendmail.mailer import SMTPMailer
 
 import sys
-if sys.platform == 'win32': # pragma: no cover
+if sys.platform == 'win32':  # pragma: no cover
     import win32file
-    _os_link = lambda src, dst: win32file.CreateHardLink(dst, src, None)
+
+    def _os_link(src, dst):
+        return win32file.CreateHardLink(dst, src, None)
 else:
     _os_link = os.link
 
@@ -56,9 +57,9 @@
 # Any error conditions not depicted on the diagram will provoke the catch-all
 # exception logging of the ``run`` method.
 #
-# In the diagram the "message file" is the file in the maildir's "cur" directory
-# that contains the message and "tmp file" is a hard link to the message file
-# created in the maildir's "tmp" directory.
+# In the diagram the "message file" is the file in the maildir's "cur"
+# directory that contains the message and "tmp file" is a hard link to the
+# message file created in the maildir's "tmp" directory.
 #
 #           ( start trying to deliver a message )
 #                            |
@@ -101,6 +102,7 @@
 #                            V                    |
 #                  ( message delivered )<---------+
 
+
 class QueueProcessorThread(threading.Thread):
     """This thread is started at configuration time from the
     `mail:queuedDelivery` directive handler if processorThread is True.
@@ -113,8 +115,8 @@ class QueueProcessorThread(threading.Thread):
     mailer = None
 
     def __init__(self, interval=3.0):
-        threading.Thread.__init__(self,
-                                  name="zope.sendmail.queue.QueueProcessorThread")
+        threading.Thread.__init__(
+            self, name="zope.sendmail.queue.QueueProcessorThread")
         self.interval = interval
         self._lock = threading.Lock()
         self.setDaemon(True)
@@ -208,8 +210,9 @@ def _process_one_file(self, filename):
             # comment above this class
 
             # find the age of the tmp file (if it exists)
-            mtime = self._action_if_exists(tmp_filename,
-                                           lambda fname: os.stat(fname)[stat.ST_MTIME])
+            mtime = self._action_if_exists(
+                tmp_filename,
+                lambda fname: os.stat(fname).st_mtime)
             age = time.time() - mtime if mtime is not None else None
 
             # if the tmp file exists, check its age
@@ -222,12 +225,13 @@ def _process_one_file(self, filename):
                     try:
                         os.unlink(tmp_filename)
                     except OSError as e:
-                        if e.errno == errno.ENOENT: # file does not exist
+                        if e.errno == errno.ENOENT:  # file does not exist
                             # it looks like someone else removed the tmp
                             # file, that's fine, we'll try to deliver the
                             # message again later
                             return
-                        # XXX: we're silently ignoring the exception here. Is that right?
+                        # XXX: we're silently ignoring the exception here.
+                        # Is that right?
                         # If permissions or something are not right, we'll fail
                         # on _os_link later on.
                     # if we get here, the file existed, but was too
@@ -247,7 +251,7 @@ def _process_one_file(self, filename):
             try:
                 os.utime(filename, None)
             except OSError as e:
-                if e.errno == errno.ENOENT: # file does not exist
+                if e.errno == errno.ENOENT:  # file does not exist
                     # someone removed the message before we could
                     # touch it, no need to complain, we'll just keep
                     # going
@@ -257,15 +261,14 @@ def _process_one_file(self, filename):
             # creating this hard link will fail if another process is
             # also sending this message
             try:
-                #os.link(filename, tmp_filename)
                 _os_link(filename, tmp_filename)
             except OSError as e:
-                if e.errno == errno.EEXIST: # file exists, *nix
+                if e.errno == errno.EEXIST:  # file exists, *nix
                     # it looks like someone else is sending this
                     # message too; we'll try again later
                     return
                 # XXX: Silently ignoring all other errno
-            except Exception as e: # pragma: no cover
+            except Exception as e:  # pragma: no cover
                 if e[0] == 183 and e[1] == 'CreateHardLink':
                     # file exists, win32
                     return
@@ -299,7 +302,6 @@ def _process_one_file(self, filename):
                             "Discarding email from %s to %s due to"
                             " a permanent error: %s",
                             fromaddr, ", ".join(toaddrs), str(e))
-                        #os.link(filename, rejected_filename)
                         _os_link(filename, rejected_filename)
                     else:
                         # Log an error and retry later
@@ -330,7 +332,6 @@ def _process_one_file(self, filename):
                     "Error while sending mail : %s ",
                     filename, exc_info=True)
 
-
     def stop(self):
         self._stopped = True
         self._lock.acquire()
@@ -364,55 +365,67 @@ class ConsoleApp(object):
     ]
 
     parser = argparse.ArgumentParser()
-    parser.add_argument('--daemon', action='store_true',
-                        help=("Run in daemon mode, periodically checking queue "
-                              "and sending messages.  Default is to send all "
-                              "messages in queue once and exit."))
-    parser.add_argument('--interval', metavar='<#secs>', type=float, default=3,
-                        help=("How often to check queue when in daemon mode. "
-                              "Default is %(default)s seconds."))
-    smtp_group = parser.add_argument_group("SMTP Server",
-                                           "Connection information for the SMTP server")
-    smtp_group.add_argument('--hostname', default='localhost',
-                            help=("Name of SMTP host to use for delivery.  Default is "
-                                  "%(default)s."))
-    smtp_group.add_argument('--port', type=int, default=25,
-                            help=("Which port on SMTP server to deliver mail to. "
-                                  "Default is %(default)s."))
-
-    auth_group = parser.add_argument_group("Authentication",
-                                           ("Authentication information for the SMTP server. "
-                                            "If one is provided, they must both be. One or both "
-                                            "can be provided in the --config file."))
-    auth_group.add_argument('--username',
-                            help=("Username to use to log in to SMTP server.  Default "
-                                  "is none."))
-    auth_group.add_argument('--password',
-                            help=("Password to use to log in to SMTP server.  Must be "
-                                  "specified if username is specified."))
+    parser.add_argument(
+        '--daemon', action='store_true',
+        help=("Run in daemon mode, periodically checking queue "
+              "and sending messages.  Default is to send all "
+              "messages in queue once and exit."))
+    parser.add_argument(
+        '--interval', metavar='<#secs>', type=float, default=3,
+        help=("How often to check queue when in daemon mode. "
+              "Default is %(default)s seconds."))
+    smtp_group = parser.add_argument_group(
+        "SMTP Server",
+        "Connection information for the SMTP server")
+    smtp_group.add_argument(
+        '--hostname', default='localhost',
+        help=("Name of SMTP host to use for delivery.  Default is "
+              "%(default)s."))
+    smtp_group.add_argument(
+        '--port', type=int, default=25,
+        help=("Which port on SMTP server to deliver mail to. "
+              "Default is %(default)s."))
+
+    auth_group = parser.add_argument_group(
+        "Authentication",
+        ("Authentication information for the SMTP server. "
+         "If one is provided, they must both be. One or both "
+         "can be provided in the --config file."))
+    auth_group.add_argument(
+        '--username',
+        help=("Username to use to log in to SMTP server.  Default "
+              "is none."))
+    auth_group.add_argument(
+        '--password',
+        help=("Password to use to log in to SMTP server.  Must be "
+              "specified if username is specified."))
     del auth_group
     tls_group = smtp_group.add_mutually_exclusive_group()
-    tls_group.add_argument('--force-tls', action='store_true',
-                           help=("Do not connect if TLS is not available.  Not "
-                                 "enabled by default."))
-    tls_group.add_argument('--no-tls', action='store_true',
-                           help=("Do not use TLS even if is available.  Not enabled "
-                                 "by default."))
+    tls_group.add_argument(
+        '--force-tls', action='store_true',
+        help=("Do not connect if TLS is not available.  Not "
+              "enabled by default."))
+    tls_group.add_argument(
+        '--no-tls', action='store_true',
+        help=("Do not use TLS even if is available.  Not enabled "
+              "by default."))
     del tls_group
     del smtp_group
-    parser.add_argument('--config', metavar='<inifile>',
-                        type=argparse.FileType(),
-                        help=("Get configuration from specified ini file; it must "
-                              "contain a section [%s] that can contain the "
-                              "following keys: %s. If you specify the queue path "
-                              "in the ini file, you don't need to specify it on "
-                              "the command line. With the exception of the queue path, "
-                              "options specified in the ini file override options on the "
-                              "command line." % (INI_SECTION, ', '.join(INI_NAMES))))
-    parser.add_argument("maildir", default=None, nargs="?",
-                        help=("The path to the mail queue directory."
-                              "If not given, it must be found in the --config file."
-                              "If given, this overrides a value in the --config file"))
+    parser.add_argument(
+        '--config', metavar='<inifile>',
+        type=argparse.FileType(),
+        help=("Get configuration from specified ini file; it must "
+              "contain a section [%s] that can contain the "
+              "following keys: %s. If you specify the queue path "
+              "in the ini file, you don't need to specify it on "
+              "the command line. With the exception of the queue path, "
+              "options specified in the ini file override options on the "
+              "command line." % (INI_SECTION, ', '.join(INI_NAMES))))
+    parser.add_argument(
+        "maildir", default=None, nargs="?",
+        help=("The path to the mail queue directory."
+              "If not given, it must be found in the --config file."
+              "If given, this overrides a value in the --config file"))
 
     daemon = False
     interval = 3
@@ -432,8 +445,9 @@ def __init__(self, argv=None, verbose=True):
         self.script_name = argv[0]
         self.verbose = verbose
         self._process_args(argv[1:])
-        self.mailer = self.MailerKind(self.hostname, self.port, self.username,
-                                      self.password, self.no_tls, self.force_tls)
+        self.mailer = self.MailerKind(
+            self.hostname, self.port, self.username, self.password,
+            self.no_tls, self.force_tls)
 
     def main(self):
         queue = self.QueueProcessorKind(self.interval)
@@ -479,6 +493,7 @@ def _load_config(self, path):
         self.no_tls = boolean(config.get(section, "no_tls"))
         self.queue_path = string_or_none(config.get(section, "queue_path"))
 
+
 def run(argv=None):
     logging.basicConfig()
     app = ConsoleApp(argv)
diff --git a/src/zope/sendmail/tests/test_delivery.py b/src/zope/sendmail/tests/test_delivery.py
index b94d276..80c2da2 100644
--- a/src/zope/sendmail/tests/test_delivery.py
+++ b/src/zope/sendmail/tests/test_delivery.py
@@ -31,6 +31,7 @@
 from zope.sendmail.delivery import AbstractMailDelivery
 from zope.sendmail.delivery import DirectMailDelivery
 
+
 @implementer(IMailer)
 class MailerStub(object):
 
@@ -54,13 +55,14 @@ def testInterface(self):
         self.assertEqual(manager.callable, object)
         self.assertEqual(manager.args, (1, 2))
         # required by IDataManager
-        self.assertTrue(isinstance(manager.sortKey(), str))
+        self.assertIsInstance(manager.sortKey(), str)
 
     def test_successful_commit(self):
         # Regression test for http://www.zope.org/Collectors/Zope3-dev/590
         from zope.sendmail.delivery import MailDataManager
 
         _success = []
+
         def _on_success(*args):
             _success.append(args)
 
@@ -76,7 +78,6 @@ def _on_abort(*args):
         manager.tpc_finish(xact)
         self.assertEqual(_success, [('foo', 'bar')])
 
-
     def test_unsuccessful_commit(self):
         # Regression test for http://www.zope.org/Collectors/Zope3-dev/590
         from zope.sendmail.delivery import MailDataManager
@@ -101,6 +102,11 @@ def _on_abort(*args):
 
 class TestAbstractMailDelivery(unittest.TestCase):
 
+    # Avoid DeprecationWarning for assertRaisesRegexp on Python 3 while
+    # coping with Python 2 not having the Regex spelling variant
+    assertRaisesRegex = getattr(unittest.TestCase, 'assertRaisesRegex',
+                                unittest.TestCase.assertRaisesRegexp)
+
     def test_bad_message_id(self):
         class Parser(object):
             def parsestr(self, s):
@@ -112,8 +118,8 @@ def parsestr(self, s):
         email.parser.Parser = Parser
 
         delivery = AbstractMailDelivery()
-        with self.assertRaisesRegexp(ValueError,
-                                     "Malformed Message-Id header"):
+        with self.assertRaisesRegex(ValueError,
+                                    "Malformed Message-Id header"):
             delivery.send(None, None, None)
 
 
@@ -148,7 +154,7 @@ def testSend(self):
 
         mailer.sent_messages = []
         msgid = delivery.send(fromaddr, toaddrs, message)
-        self.assertTrue('@' in msgid)
+        self.assertIn('@', msgid)
         self.assertEqual(mailer.sent_messages, [])
         transaction.commit()
         self.assertEqual(len(mailer.sent_messages), 1)
@@ -156,7 +162,7 @@ def testSend(self):
         self.assertEqual(mailer.sent_messages[0][1], toaddrs)
         self.assertTrue(mailer.sent_messages[0][2].endswith(message))
         new_headers = mailer.sent_messages[0][2][:-len(message)]
-        self.assertTrue(new_headers.find('Message-Id: <%s>' % msgid) != -1)
+        self.assertIn('Message-Id: <%s>' % msgid, new_headers)
 
         mailer.sent_messages = []
         msgid = delivery.send(fromaddr, toaddrs, opt_headers + message)
@@ -226,7 +232,6 @@ def send(self):
         self.assertIn("does not provide a vote method", str(w[0]))
 
 
-
 class MaildirWriterStub(object):
 
     data = ''
@@ -278,6 +283,7 @@ def newMessage(self):
         self.msgs.append(m)
         return m
 
+
 class WritableMaildirStub(MaildirStub):
 
     STUB_DEFAULT_MESSAGE_LINES = (
@@ -299,7 +305,8 @@ def __init__(self, test, *args, **kwargs):
         self.stub_directory = tempfile.mkdtemp(suffix=".test_maildir")
         test.addCleanup(shutil.rmtree, self.stub_directory)
 
-    def stub_createFile(self, filename="message", lines=STUB_DEFAULT_MESSAGE_LINES):
+    def stub_createFile(self, filename="message",
+                        lines=STUB_DEFAULT_MESSAGE_LINES):
         """
         Create a new file in the temporary directory.
 
@@ -387,6 +394,7 @@ def send(self, fromaddr, toaddrs, message):
 
     abort = None
 
+
 @implementer(IMailer)
 class SMTPResponseExceptionMailerStub(object):
 
@@ -444,12 +452,14 @@ def testSend(self):
 
         MaildirWriterStub.commited_messages = []
         msgid = delivery.send(fromaddr, toaddrs, message)
-        self.assertTrue('@' in msgid)
+        self.assertIn('@', msgid)
         self.assertEqual(MaildirWriterStub.commited_messages, [])
         self.assertEqual(MaildirWriterStub.aborted_messages, [])
         transaction.commit()
         self.assertEqual(len(MaildirWriterStub.commited_messages), 1)
-        self.assertTrue(MaildirWriterStub.commited_messages[0].endswith(message))
+        self.assertTrue(
+            MaildirWriterStub.commited_messages[0].endswith(message)
+        )
         new_headers = MaildirWriterStub.commited_messages[0][:-len(message)]
         self.assertIn('Message-Id: <%s>' % msgid, new_headers)
         self.assertIn('X-Zope-From: %s' % fromaddr, new_headers)
@@ -463,7 +473,3 @@ def testSend(self):
         transaction.abort()
         self.assertEqual(MaildirWriterStub.commited_messages, [])
         self.assertEqual(len(MaildirWriterStub.aborted_messages), 1)
-
-
-def test_suite():
-    return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/sendmail/tests/test_directives.py b/src/zope/sendmail/tests/test_directives.py
index f0e6de8..c3e0b2d 100644
--- a/src/zope/sendmail/tests/test_directives.py
+++ b/src/zope/sendmail/tests/test_directives.py
@@ -34,10 +34,12 @@
 class MaildirStub(object):
     pass
 
+
 @implementer(IMailer)
 class Mailer(object):
     pass
 
+
 class MockQueueProcessorThread(object):
 
     def setMailer(self, mailer):
@@ -111,10 +113,3 @@ def test_zcml_without_registered_smtp_mailer(self):
 
     def test_zcml_without_registered_mailer(self):
         self._check_zcml_without_registration(self.testMailer, 'test.mailer')
-
-
-def test_suite():
-    return unittest.defaultTestLoader.loadTestsFromName(__name__)
-
-if __name__ == '__main__':
-    unittest.main()
diff --git a/src/zope/sendmail/tests/test_maildir.py b/src/zope/sendmail/tests/test_maildir.py
index 11cc419..606abd4 100644
--- a/src/zope/sendmail/tests/test_maildir.py
+++ b/src/zope/sendmail/tests/test_maildir.py
@@ -25,11 +25,13 @@
 from zope.sendmail.maildir import Maildir
 from zope.sendmail.interfaces import IMaildirMessageWriter
 
+
 class FakeSocketModule(object):
 
     def gethostname(self):
         return 'myhostname'
 
+
 class FakeTimeModule(object):
 
     _timer = 1234500000
@@ -40,6 +42,7 @@ def time(self):
     def sleep(self, n):
         self._timer += n
 
+
 class FakeOsPathModule(object):
 
     def __init__(self, files, dirs):
@@ -81,7 +84,7 @@ class FakeOsModule(object):
         '/path/to/maildir/tmp/1234500000.4242.myhostname.*': stat.S_IFREG,
         '/path/to/maildir/tmp/1234500001.4242.myhostname.*': stat.S_IFREG,
         '/path/to/regularfile': stat.S_IFREG,
-        '/path/to/emptydirectory': stat.S_IFDIR,
+        '/path/to/emptydir': stat.S_IFDIR,
     }
     _listdir = {
         '/path/to/maildir/new': ['1', '2', '.svn'],
@@ -129,10 +132,10 @@ def rename(self, old, new):
 
     def open(self, filename, flags, mode=0o777):
         if (flags & os.O_EXCL and flags & os.O_CREAT
-            and self.access(filename, 0)):
+                and self.access(filename, 0)):
             raise OSError(errno.EEXIST, 'file already exists')
         if not flags & os.O_CREAT and not self.access(filename, 0):
-            raise OSError('file not found') # pragma: no cover
+            raise OSError('file not found')  # pragma: no cover
         fd = max(list(self._descriptors.keys()) + [2]) + 1
         self._descriptors[fd] = filename, flags, mode
         return fd
@@ -140,7 +143,7 @@ def open(self, filename, flags, mode=0o777):
     def fdopen(self, fd, mode='r'):
         try:
             filename, flags, _permissions = self._descriptors[fd]
-        except KeyError: # pragma: no cover
+        except KeyError:  # pragma: no cover
             raise AssertionError('os.fdopen() called with an unknown'
                                  ' file descriptor')
         assert mode == 'w'
@@ -210,8 +213,8 @@ def test_factory(self):
         self.assertRaises(ValueError, Maildir, '/path/to/regularfile', True)
 
         # Case 4: it is a directory, but not a maildir
-        self.assertRaises(ValueError, Maildir, '/path/to/emptydirectory', False)
-        self.assertRaises(ValueError, Maildir, '/path/to/emptydirectory', True)
+        self.assertRaises(ValueError, Maildir, '/path/to/emptydir', False)
+        self.assertRaises(ValueError, Maildir, '/path/to/emptydir', True)
 
     def test_iteration(self):
         m = Maildir('/path/to/maildir')
@@ -230,6 +233,7 @@ def test_newMessage(self):
 
     def test_newMessage_error(self):
         m = Maildir('/path/to/maildir')
+
         def open(*args):
             raise OSError(errno.EADDRINUSE, "")
         self.fake_os_module.open = open
@@ -303,10 +307,3 @@ def test_message_writer_unicode(self):
                          b'fe\xc3\xa8 fi\xc3\xa8 fo\xc3\xa8 fo\xc3\xb2')
         writer.close()
         self.assertTrue(writer._fd._closed)
-
-
-def test_suite():
-    return unittest.defaultTestLoader.loadTestsFromName(__name__)
-
-if __name__ == '__main__':
-    unittest.main()
diff --git a/src/zope/sendmail/tests/test_mailer.py b/src/zope/sendmail/tests/test_mailer.py
index 891d70d..5154772 100644
--- a/src/zope/sendmail/tests/test_mailer.py
+++ b/src/zope/sendmail/tests/test_mailer.py
@@ -26,6 +26,7 @@
 # This works for both, Python 2 and 3.
 port_types = (int, str)
 
+
 class SMTP(object):
 
     fail_on_quit = False
@@ -85,12 +86,16 @@ class TestSMTPMailer(unittest.TestCase):
 
     SMTPClass = SMTP
 
+    # Avoid DeprecationWarning for assertRaisesRegexp on Python 3 while
+    # coping with Python 2 not having the Regex spelling variant
+    assertRaisesRegex = getattr(unittest.TestCase, 'assertRaisesRegex',
+                                unittest.TestCase.assertRaisesRegexp)
+
     def _makeSMTP(self, h, p):
         self.smtp = self.SMTPClass(h, p)
         self.smtp_hook(self.smtp)
         return self.smtp
 
-
     def setUp(self, port=None):
         self.smtp = None
         if port is None:
@@ -122,8 +127,10 @@ def test_send_multiple_same_mailer(self):
         # The mailer re-opens itself as needed when sending
         # multiple mails.
         smtps = []
+
         def hook(smtp):
             smtps.append(smtp)
+
         self.smtp_hook = hook
         for run in (1, 2):
             fromaddr = 'me@example.com' + str(run)
@@ -138,15 +145,15 @@ def hook(smtp):
 
         self.assertEqual(2, len(smtps))
 
-
     def test_send_multiple_threads(self):
         import threading
 
         results = []
+
         def run():
             try:
                 self.test_send_multiple_same_mailer()
-            except BaseException as e: # pragma: no cover
+            except BaseException as e:  # pragma: no cover
                 results.append(e)
                 raise
             else:
@@ -186,8 +193,8 @@ def test_send_auth_unicode(self):
         fromaddr = 'me@example.com'
         toaddrs = ('you@example.com', 'him@example.com')
         msgtext = 'Headers: headers\n\nbodybodybody\n-- \nsig\n'
-        self.mailer.username = u'f\u00f8\u00f8' # double o slash
-        self.mailer.password = u'\u00e9vil' # e acute
+        self.mailer.username = u'f\u00f8\u00f8'  # double o slash
+        self.mailer.password = u'\u00e9vil'  # e acute
         self.mailer.hostname = 'spamrelay'
         self.mailer.port = 31337
         self.mailer.send(fromaddr, toaddrs, msgtext)
@@ -198,8 +205,8 @@ def test_send_auth_nonascii(self):
         fromaddr = 'me@example.com'
         toaddrs = ('you@example.com', 'him@example.com')
         msgtext = 'Headers: headers\n\nbodybodybody\n-- \nsig\n'
-        self.mailer.username = b'f\xc3\xb8\xc3\xb8' # double o slash
-        self.mailer.password = b'\xc3\xa9vil' # e acute
+        self.mailer.username = b'f\xc3\xb8\xc3\xb8'  # double o slash
+        self.mailer.password = b'\xc3\xa9vil'  # e acute
         self.mailer.hostname = 'spamrelay'
         self.mailer.port = 31337
         self.mailer.send(fromaddr, toaddrs, msgtext)
@@ -220,7 +227,6 @@ def test_send_failQuit(self):
         self.assertTrue(not self.smtp.quitted)
         self.assertTrue(self.smtp.closed)
 
-
     def test_vote_bad_connection(self):
 
         def hook(smtp):
@@ -228,8 +234,8 @@ def hook(smtp):
             smtp.helo = lambda: (100, "Nope")
         self.smtp_hook = hook
 
-        with self.assertRaisesRegexp(RuntimeError,
-                                     "Error sending HELO to the SMTP server"):
+        with self.assertRaisesRegex(RuntimeError,
+                                    "Error sending HELO to the SMTP server"):
             self.mailer.vote(None, None, None)
 
     def test_abort_no_conn(self):
@@ -238,8 +244,10 @@ def test_abort_no_conn(self):
     def test_abort_fails_call_close(self):
         class Conn(object):
             closed = False
+
             def quit(self):
                 raise SSLError()
+
             def close(self):
                 self.closed = True
 
@@ -258,20 +266,22 @@ def has_extn(self, name):
         self.mailer.force_tls = True
         self.mailer.connection = Conn()
 
-        with self.assertRaisesRegexp(RuntimeError,
-                                     'TLS is not available'):
+        with self.assertRaisesRegex(RuntimeError,
+                                    'TLS is not available'):
             self.mailer.send(None, None, None)
 
     def test_send_no_esmtp_with_username(self):
         class Conn(object):
             does_esmtp = False
+
             def has_extn(self, *args):
                 return False
 
         self.mailer.connection = Conn()
         self.mailer.username = 'user'
-        with self.assertRaisesRegexp(RuntimeError,
-                                     "Mailhost does not support ESMTP but a username"):
+        with self.assertRaisesRegex(
+                RuntimeError,
+                "Mailhost does not support ESMTP but a username"):
             self.mailer.send(None, None, None)
 
 
@@ -280,10 +290,8 @@ class TestSMTPMailerWithNoEHLO(TestSMTPMailer):
     SMTPClass = SMTPWithNoEHLO
 
     def test_send_auth(self):
-        self.skipTest("This test requires ESMTP, which we're intentionally not enabling")
+        self.skipTest(
+            "This test requires ESMTP, which we're intentionally not enabling")
 
     test_send_auth_unicode = test_send_auth
     test_send_auth_nonascii = test_send_auth
-
-def test_suite():
-    return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/sendmail/tests/test_queue.py b/src/zope/sendmail/tests/test_queue.py
index 9baac58..a1a1aaa 100644
--- a/src/zope/sendmail/tests/test_queue.py
+++ b/src/zope/sendmail/tests/test_queue.py
@@ -42,6 +42,7 @@ class QPTesting(queue.QueueProcessorThread):
     def _makeMaildir(self, path):
         return WritableMaildirStub(self.test, path)
 
+
 class SMTPRecipientsRefusedMailerStub(object):
 
     def __init__(self, recipients):
@@ -51,6 +52,7 @@ def send(self, fromaddr, toaddrs, message):
         import smtplib
         raise smtplib.SMTPRecipientsRefused(self.recipients)
 
+
 @contextmanager
 def patched(module, attr, func):
     orig = getattr(module, attr)
@@ -60,6 +62,7 @@ def patched(module, attr, func):
     finally:
         setattr(module, attr, orig)
 
+
 class TestQueueProcessorThread(unittest.TestCase):
 
     def setUp(self):
@@ -76,10 +79,12 @@ def setUp(self):
     def _assertEmptyErrorLog(self):
         self.assertEqual(self.thread.log.errors, [])
 
-    def _assertErrorLog(self,
-                        From=WritableMaildirStub.STUB_DEFAULT_MESSAGE_SENT[0],
-                        to=", ".join(WritableMaildirStub.STUB_DEFAULT_MESSAGE_SENT[1]),
-                        exception_kind=None):
+    def _assertErrorLog(
+        self,
+        From=WritableMaildirStub.STUB_DEFAULT_MESSAGE_SENT[0],
+        to=", ".join(WritableMaildirStub.STUB_DEFAULT_MESSAGE_SENT[1]),
+        exception_kind=None,
+    ):
         expected = ('Error while sending mail from %s to %s.',
                     (From, to,),
                     {'exc_info': True},)
@@ -104,8 +109,9 @@ def _assertGenericErrorLog(self, filename="message",
 
     def _assertTmpMessagePathDoesNotExist(self, filename="message"):
         full_path = self.md.stub_getTmpFilename(filename)
-        self.assertFalse(os.path.exists(full_path),
-                         "The temporary path '%s' should not exist" % full_path)
+        self.assertFalse(
+            os.path.exists(full_path),
+            "The temporary path '%s' should not exist" % full_path)
 
     def _assertTmpMessagePathExists(self, filename="message"):
         full_path = self.md.stub_getTmpFilename(filename)
@@ -128,7 +134,8 @@ def _assertMessagePathDoesNotExist(self, filename="message"):
                          "The path '%s' should not exist" % full_path)
 
     def test_makeMaildir_creates(self):
-        md = queue.QueueProcessorThread()._makeMaildir(os.path.join(self.dir, 'testing'))
+        md = queue.QueueProcessorThread()._makeMaildir(
+            os.path.join(self.dir, 'testing'))
         self.assertTrue(os.path.exists(md.path))
 
     def test_threadName(self):
@@ -220,8 +227,10 @@ def test_smtp_recipients_refused(self):
 
     def test_stop_while_running(self):
         test = self
+
         class Maildir(object):
             count = 0
+
             def __iter__(self):
                 return self
 
@@ -232,7 +241,7 @@ def __next__(self):
                     return
                 raise AssertionError("Should have stopped")
 
-            next = __next__ # Python 2
+            next = __next__  # Python 2
 
         self.thread.setMaildir(Maildir())
         self.thread.run()
@@ -254,6 +263,7 @@ def test_tmpfile_cannot_stat(self):
         tmp_file = self.md.stub_createTmpFile()
 
         err = OSError(tmp_file)
+
         def stat(fname):
             # Note that this interferes with debuggers
             self.assertEqual(fname, tmp_file)
@@ -269,7 +279,6 @@ def stat(fname):
         # And we logged the random error
         self._assertGenericErrorLog(exception=err)
 
-
     def test_tmpfile_too_old(self):
         self.md.stub_createFile()
         self.md.stub_createTmpFile()
@@ -339,9 +348,9 @@ def utime(fname, atm):
         self._assertMessagePathExists()
         self._assertEmptyErrorLog()
 
-
     def test_run_forever(self):
         import time
+
         class DoneSleeping(Exception):
             pass
 
@@ -354,8 +363,6 @@ def sleep(i):
                 self.thread.run()
 
 
-
-
 test_ini = """[app:zope-sendmail]
 interval = 33
 hostname = testhost
@@ -367,6 +374,7 @@ def sleep(i):
 queue_path = hammer/dont/hurt/em
 """
 
+
 class TestConsoleApp(unittest.TestCase):
     def setUp(self):
         from zope.sendmail.delivery import QueuedMailDelivery
@@ -386,7 +394,7 @@ def tearDown(self):
     def _make_one(self, cmdline):
         cmdline = cmdline.split() if isinstance(cmdline, str) else cmdline
         with patched(sys, 'stdout', self.stdout), \
-             patched(sys, 'stderr', self.stderr):
+                patched(sys, 'stderr', self.stderr):
             return ConsoleApp(cmdline, verbose=False)
 
     def _get_output(self):
@@ -418,9 +426,11 @@ def test_args_processing_no_queue_path(self):
 
     def test_args_processing_almost_all_options(self):
         # use (almost) all of the options
-        cmdline = "zope-sendmail --daemon --interval 7 --hostname foo --port 75 " \
-            "--username chris --password rossi --force-tls " \
+        cmdline = (
+            "zope-sendmail --daemon --interval 7 --hostname foo --port 75 "
+            "--username chris --password rossi --force-tls "
             "%s" % self.dir
+        )
         app = self._make_one(cmdline)
         self.assertEqual("zope-sendmail", app.script_name)
         self.assertEqual(self.dir, app.queue_path)
@@ -447,8 +457,8 @@ def test_args_processing_username_without_password(self):
         with self.assertRaises(SystemExit):
             self._make_one(cmdline)
 
-        self.assertIn('Must use username and password together', self._get_output())
-
+        self.assertIn('Must use username and password together',
+                      self._get_output())
 
     def test_args_processing_force_tls_and_no_tls(self):
         # test force_tls and no_tls
@@ -457,7 +467,8 @@ def test_args_processing_force_tls_and_no_tls(self):
         with self.assertRaises(SystemExit):
             self._make_one(cmdline)
 
-        self.assertIn('--no-tls: not allowed with argument', self._get_output())
+        self.assertIn('--no-tls: not allowed with argument',
+                      self._get_output())
 
     def test_ini_parse(self):
         ini_path = os.path.join(self.dir, "zope-sendmail.ini")
@@ -504,8 +515,8 @@ def test_run(self):
         cmdline = ['sendmail', self.dir]
 
         with patched(QPTesting, 'test', self), \
-             patched(ConsoleApp, 'QueueProcessorKind', QPTesting), \
-             patched(ConsoleApp, 'MailerKind', MailerStub):
+                patched(ConsoleApp, 'QueueProcessorKind', QPTesting), \
+                patched(ConsoleApp, 'MailerKind', MailerStub):
             queue.run(cmdline)
 
     def test_help(self):
@@ -516,6 +527,3 @@ def test_help(self):
 
         self.assertIn('usage', self._get_output())
         self.assertEqual(exc.exception.code, 0)
-
-def test_suite():
-    return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/sendmail/tests/test_vocabulary.py b/src/zope/sendmail/tests/test_vocabulary.py
index f6e9d03..b5e4742 100644
--- a/src/zope/sendmail/tests/test_vocabulary.py
+++ b/src/zope/sendmail/tests/test_vocabulary.py
@@ -16,10 +16,11 @@
 
 import doctest
 import unittest
+
 from zope.component.testing import PlacelessSetup
 
-class MailDeliveryNamesTests(PlacelessSetup,
-                             unittest.TestCase):
+
+class MailDeliveryNamesTests(PlacelessSetup, unittest.TestCase):
 
     _marker = object()
 
diff --git a/src/zope/sendmail/vocabulary.py b/src/zope/sendmail/vocabulary.py
index ff99b90..a1a1f94 100644
--- a/src/zope/sendmail/vocabulary.py
+++ b/src/zope/sendmail/vocabulary.py
@@ -21,6 +21,7 @@
 from zope.schema.vocabulary import SimpleVocabulary, SimpleTerm
 from zope.sendmail.interfaces import IMailDelivery
 
+
 def MailDeliveryNames(context=None):
     """Vocabulary with names of mail delivery utilities
 
@@ -52,4 +53,5 @@ def MailDeliveryNames(context=None):
     terms = [SimpleTerm(name) for name, util in utils]
     return SimpleVocabulary(terms)
 
+
 directlyProvides(MailDeliveryNames, IVocabularyFactory)
diff --git a/src/zope/sendmail/zcml.py b/src/zope/sendmail/zcml.py
index c11275f..dd601b4 100644
--- a/src/zope/sendmail/zcml.py
+++ b/src/zope/sendmail/zcml.py
@@ -30,15 +30,17 @@
 try:
     from zope.component.security import proxify
     from zope.security.zcml import Permission
-except ImportError: # pragma: no cover
+except ImportError:  # pragma: no cover
     SECURITY_SUPPORT = False
     Permission = TextLine
 
     def _assertPermission(permission, interfaces, component):
-        raise ConfigurationError("security proxied components are not "
-                                 "supported because zope.security is not available")
+        raise ConfigurationError(
+            "security proxied components are not "
+            "supported because zope.security is not available")
 else:
     SECURITY_SUPPORT = True
+
     def _assertPermission(permission, interfaces, component):
         return proxify(component, provides=interfaces, permission=permission)
 
@@ -49,7 +51,7 @@ class IDeliveryDirective(Interface):
 
     name = TextLine(
         title=u"Name",
-        description=u'Specifies the Delivery name of the mail utility. '\
+        description=u'Specifies the Delivery name of the mail utility. '
                     u'The default is "Mail".',
         default=u"Mail",
         required=False)
@@ -81,6 +83,7 @@ class IQueuedDeliveryDirective(IDeliveryDirective):
         required=False,
         default=True)
 
+
 def _get_mailer(mailer):
     try:
         return getUtility(IMailer, mailer)
@@ -111,10 +114,12 @@ def createQueuedDelivery():
         callable=createQueuedDelivery,
         args=())
 
+
 class IDirectDeliveryDirective(IDeliveryDirective):
     """This directive creates and registers a global direct mail utility. It
     should be only called once during startup."""
 
+
 def directDelivery(_context, mailer, permission=None, name="Mail"):
 
     def createDirectDelivery():
@@ -131,6 +136,7 @@ def createDirectDelivery():
         callable=createDirectDelivery,
         args=())
 
+
 class IMailerDirective(Interface):
     """A generic directive registering a mailer for the mail utility."""
 
@@ -165,6 +171,7 @@ class ISMTPMailerDirective(IMailerDirective):
         description=u"A password for SMTP AUTH.",
         required=False)
 
+
 def smtpMailer(_context, name, hostname="localhost", port="25",
                username=None, password=None):
     _context.action(