Multiple changes (#31)

* Add support for Python 3.11.
* Lint the code.
* Improve error handling in test.
* Bumped version for breaking release.
* Drop support for Python 2.7, 3.5, 3.6.

Co-authored-by: Gil Forcada Codinachs <gil.gnome@gmail.com>

20 files changed, 185 insertions, 140 deletions

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index d31f648..d8889f3 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -17,32 +17,30 @@ jobs:
       fail-fast: false
       matrix:
         os:
-        - ubuntu
+        - ["ubuntu", "ubuntu-20.04"]
         config:
         # [Python version, tox env]
         - ["3.9",   "lint"]
-        - ["2.7",   "py27"]
-        - ["3.5",   "py35"]
-        - ["3.6",   "py36"]
         - ["3.7",   "py37"]
         - ["3.8",   "py38"]
         - ["3.9",   "py39"]
         - ["3.10",  "py310"]
-        - ["pypy2", "pypy"]
-        - ["pypy3", "pypy3"]
+        - ["3.11",  "py311"]
+        - ["pypy-3.9", "pypy3"]
         - ["3.9",   "docs"]
         - ["3.9",   "coverage"]
 
-    runs-on: ${{ matrix.os }}-latest
+    runs-on: ${{ matrix.os[1] }}
+    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
     name: ${{ matrix.config[1] }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Set up Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.config[0] }}
     - name: Pip cache
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       with:
         path: ~/.cache/pip
         key: ${{ runner.os }}-pip-${{ matrix.config[0] }}-${{ hashFiles('setup.*', 'tox.ini') }}
@@ -58,7 +56,7 @@ jobs:
     - name: Coverage
       if: matrix.config[1] == 'coverage'
       run: |
-        pip install coveralls coverage-python-version
+        pip install coveralls
         coveralls --service=github
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.gitignore b/.gitignore
index c724a76..1f321f5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,4 +28,5 @@ lib64
 log/
 parts/
 pyvenv.cfg
+testing.log
 var/
diff --git a/.meta.toml b/.meta.toml
index 7bb3250..f0ea76b 100644
--- a/.meta.toml
+++ b/.meta.toml
@@ -2,15 +2,15 @@
 # https://github.com/zopefoundation/meta/tree/master/config/pure-python
 [meta]
 template = "pure-python"
-commit-id = "7788b0c785ec23246369c0df9c6010e0047d8645"
+commit-id = "638bf910"
 
 [python]
 with-pypy = true
-with-legacy-python = true
 with-docs = true
 with-sphinx-doctests = true
 with-windows = false
 with-future-python = false
+with-macos = false
 
 [tox]
 use-flake8 = true
diff --git a/CHANGES.rst b/CHANGES.rst
index 5f7a0ac..937553f 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -2,10 +2,12 @@
  Changes
 =========
 
-4.6.1 (unreleased)
-==================
+5.0 (unreleased)
+================
+
+- Add support for Python 3.11.
 
-- Nothing changed yet.
+- Drop support for Python 2.7, 3.5, 3.6.
 
 
 4.6.0 (2021-11-04)
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..31d95f0
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,23 @@
+<!--
+Generated from:
+https://github.com/zopefoundation/meta/tree/master/config/pure-python
+--> 
+# Contributing to zopefoundation projects
+
+The projects under the zopefoundation GitHub organization are open source and
+welcome contributions in different forms:
+
+* bug reports
+* code improvements and bug fixes
+* documentation improvements
+* pull request reviews
+
+For any changes in the repository besides trivial typo fixes you are required
+to sign the contributor agreement. See
+https://www.zope.dev/developer/becoming-a-committer.html for details.
+
+Please visit our [Developer
+Guidelines](https://www.zope.dev/developer/guidelines.html) if you'd like to
+contribute code changes and our [guidelines for reporting
+bugs](https://www.zope.dev/developer/reporting-bugs.html) if you want to file a
+bug report.
diff --git a/MANIFEST.in b/MANIFEST.in
index 8a3cd9b..52dc2ad 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,5 +1,6 @@
 # Generated from:
 # https://github.com/zopefoundation/meta/tree/master/config/pure-python
+include *.md
 include *.rst
 include *.txt
 include buildout.cfg
diff --git a/setup.cfg b/setup.cfg
index 8b04203..544de16 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,7 +1,7 @@
 # Generated from:
 # https://github.com/zopefoundation/meta/tree/master/config/pure-python
 [bdist_wheel]
-universal = 1
+universal = 0
 
 [flake8]
 doctests = 1
@@ -12,3 +12,14 @@ ignore =
     .meta.toml
     docs/_build/html/_sources/*
     docs/_build/doctest/*
+
+[isort]
+force_single_line = True
+combine_as_imports = True
+sections = FUTURE,STDLIB,THIRDPARTY,ZOPE,FIRSTPARTY,LOCALFOLDER
+known_third_party = six, docutils, pkg_resources, pytz
+known_zope =
+known_first_party =
+default_section = ZOPE
+line_length = 79
+lines_after_imports = 2
diff --git a/setup.py b/setup.py
index e46e60c..4b2fb6d 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,9 @@
 """Setup for zope.pagetemplate package
 """
 import os
-from setuptools import setup, find_packages
+
+from setuptools import find_packages
+from setuptools import setup
 
 
 def read(*rnames):
@@ -36,9 +38,9 @@ TESTS_REQUIRE = [
 
 
 setup(name='zope.pagetemplate',
-      version='4.6.1.dev0',
+      version='5.0.dev0',
       author='Zope Foundation and Contributors',
-      author_email='zope-dev@zope.org',
+      author_email='zope-dev@zope.dev',
       description='Zope Page Templates',
       long_description=(
           read('README.rst')
@@ -51,15 +53,12 @@ setup(name='zope.pagetemplate',
           '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 :: 3.5',
-          'Programming Language :: Python :: 3.6',
           'Programming Language :: Python :: 3.7',
           'Programming Language :: Python :: 3.8',
           'Programming Language :: Python :: 3.9',
           'Programming Language :: Python :: 3.10',
+          'Programming Language :: Python :: 3.11',
           'Programming Language :: Python :: Implementation :: CPython',
           'Programming Language :: Python :: Implementation :: PyPy',
           'Natural Language :: English',
@@ -72,16 +71,11 @@ setup(name='zope.pagetemplate',
       packages=find_packages('src'),
       package_dir={'': 'src'},
       namespace_packages=['zope'],
+      python_requires='>=3.7',
       extras_require={
           'test': TESTS_REQUIRE,
-          'test:python_version == "2.7"': [
-              'zope.untrustedpython',
-          ],
           'untrusted': [
           ],
-          'untrusted:python_version == "2.7"': [
-              'zope.untrustedpython',
-          ],
           'docs': [
               'Sphinx',
               'repoze.sphinx.autointerface',
@@ -89,7 +83,6 @@ setup(name='zope.pagetemplate',
       },
       install_requires=[
           'setuptools',
-          'six',
           'zope.interface',
           'zope.component',
           'zope.tales',
diff --git a/src/zope/pagetemplate/engine.py b/src/zope/pagetemplate/engine.py
index 4eb805d..662dbcd 100644
--- a/src/zope/pagetemplate/engine.py
+++ b/src/zope/pagetemplate/engine.py
@@ -19,15 +19,19 @@ __docformat__ = 'restructuredtext'
 
 import sys
 
-from zope import component
+from zope.i18n import translate
 from zope.interface import implementer
 from zope.interface.interfaces import ComponentLookupError
 from zope.proxy import isProxy
-from zope.traversing.interfaces import IPathAdapter, ITraversable
-from zope.traversing.interfaces import TraversalError
+from zope.security.proxy import ProxyFactory
+from zope.security.proxy import removeSecurityProxy
 from zope.traversing.adapters import traversePathElement
-from zope.security.proxy import ProxyFactory, removeSecurityProxy
-from zope.i18n import translate
+from zope.traversing.interfaces import IPathAdapter
+from zope.traversing.interfaces import ITraversable
+from zope.traversing.interfaces import TraversalError
+
+from zope import component
+
 
 try:  # pragma: no cover
     # Until https://github.com/zopefoundation/zope.untrustedpython/issues/2
@@ -48,10 +52,14 @@ if HAVE_UNTRUSTED:  # pragma: no cover
         del rcompile
         del SafeBuiltins
 
-from zope.tales.expressions import PathExpr, StringExpr, NotExpr, DeferExpr
+from zope.tales.expressions import DeferExpr
+from zope.tales.expressions import NotExpr
+from zope.tales.expressions import PathExpr
 from zope.tales.expressions import SimpleModuleImporter
+from zope.tales.expressions import StringExpr
 from zope.tales.pythonexpr import PythonExpr
-from zope.tales.tales import ExpressionEngine, Context
+from zope.tales.tales import Context
+from zope.tales.tales import ExpressionEngine
 
 from zope.pagetemplate.i18n import ZopeMessageFactory as _
 
@@ -60,7 +68,7 @@ class InlineCodeError(Exception):
     pass
 
 
-class ZopeTraverser(object):
+class ZopeTraverser:
 
     def __init__(self, proxify=None):
         if proxify is None:
@@ -96,7 +104,7 @@ zopeTraverser = ZopeTraverser(ProxyFactory)
 class ZopePathExpr(PathExpr):
 
     def __init__(self, name, expr, engine):
-        super(ZopePathExpr, self).__init__(name, expr, engine, zopeTraverser)
+        super().__init__(name, expr, engine, zopeTraverser)
 
 
 trustedZopeTraverser = ZopeTraverser()
@@ -105,8 +113,7 @@ trustedZopeTraverser = ZopeTraverser()
 class TrustedZopePathExpr(PathExpr):
 
     def __init__(self, name, expr, engine):
-        super(TrustedZopePathExpr, self).__init__(name, expr, engine,
-                                                  trustedZopeTraverser)
+        super().__init__(name, expr, engine, trustedZopeTraverser)
 
 
 # Create a version of the restricted built-ins that uses a safe
@@ -238,7 +245,7 @@ class TrustedZopeContext(ZopeContextBase):
     """Evaluation context for trusted programs."""
 
 
-class AdapterNamespaces(object):
+class AdapterNamespaces:
     """Simulate tales function namespaces with adapter lookup.
 
     When we are asked for a namespace, we return an object that
@@ -350,7 +357,7 @@ class ZopeEngine(ZopeBaseEngine):
       >>> m._getframe
       Traceback (most recent call last):
         ...
-      ForbiddenAttribute: ('_getframe', <module 'sys' (built-in)>)
+      zope.security.interfaces.ForbiddenAttribute: ('_getframe', <module 'sys' (built-in)>)
 
     The results of Python expressions evaluated by this engine are
     wrapped in security proxies if the 'untrusted' extra is installed::
@@ -394,16 +401,16 @@ class ZopeEngine(ZopeBaseEngine):
       >>> o1.__name__
       'bar'
       >>> type(o1)
-      <type 'zope.security._proxy._Proxy'>
+      <class 'zope.security._proxy._Proxy'>
 
       >>> o2 = context.evaluate('foo/bar/baz')
       >>> o2.__name__
       'baz'
       >>> type(o2)
-      <type 'zope.security._proxy._Proxy'>
+      <class 'zope.security._proxy._Proxy'>
       >>> o3 = o2.__parent__
       >>> type(o3)
-      <type 'zope.security._proxy._Proxy'>
+      <class 'zope.security._proxy._Proxy'>
       >>> o1 == o3
       True
 
@@ -446,12 +453,12 @@ class ZopeEngine(ZopeBaseEngine):
 
       >>> tearDown()
 
-    """
+    """  # noqa: E501 line too long
 
     def getFunctionNamespace(self, namespacename):
         """ Returns the function namespace """
         return ProxyFactory(
-            super(ZopeEngine, self).getFunctionNamespace(namespacename))
+            super().getFunctionNamespace(namespacename))
 
 
 class TrustedZopeEngine(ZopeBaseEngine):
@@ -536,13 +543,13 @@ Engine = _Engine()
 TrustedEngine = _TrustedEngine()
 
 
-class AppPT(object):
+class AppPT:
 
     def pt_getEngine(self):
         return Engine
 
 
-class TrustedAppPT(object):
+class TrustedAppPT:
 
     def pt_getEngine(self):
         return TrustedEngine
diff --git a/src/zope/pagetemplate/i18n.py b/src/zope/pagetemplate/i18n.py
index fc47f88..0db0317 100644
--- a/src/zope/pagetemplate/i18n.py
+++ b/src/zope/pagetemplate/i18n.py
@@ -17,4 +17,6 @@ __docformat__ = 'restructuredtext'
 
 # import this as _ to create i18n messages in the zope domain
 from zope.i18nmessageid import MessageFactory
+
+
 ZopeMessageFactory = MessageFactory('zope')
diff --git a/src/zope/pagetemplate/interfaces.py b/src/zope/pagetemplate/interfaces.py
index 0812a83..75ef47f 100644
--- a/src/zope/pagetemplate/interfaces.py
+++ b/src/zope/pagetemplate/interfaces.py
@@ -13,7 +13,8 @@
 ##############################################################################
 """Interface that describes the 'macros' attribute of a PageTemplate.
 """
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute
+from zope.interface import Interface
 
 
 class IPageTemplate(Interface):
diff --git a/src/zope/pagetemplate/pagetemplate.py b/src/zope/pagetemplate/pagetemplate.py
index bd9eafb..9c875ec 100644
--- a/src/zope/pagetemplate/pagetemplate.py
+++ b/src/zope/pagetemplate/pagetemplate.py
@@ -16,19 +16,20 @@
 HTML- and XML-based template objects using TAL, TALES, and METAL.
 """
 import sys
-import six
-from zope.tal.talparser import TALParser
+
+from zope.component import queryUtility
+from zope.interface import implementer
+from zope.interface import provider
 from zope.tal.htmltalparser import HTMLTALParser
 from zope.tal.talgenerator import TALGenerator
 from zope.tal.talinterpreter import TALInterpreter
+from zope.tal.talparser import TALParser
 from zope.tales.engine import Engine
-from zope.component import queryUtility
 
-from zope.pagetemplate.interfaces import IPageTemplateSubclassing
 from zope.pagetemplate.interfaces import IPageTemplateEngine
 from zope.pagetemplate.interfaces import IPageTemplateProgram
-from zope.interface import implementer
-from zope.interface import provider
+from zope.pagetemplate.interfaces import IPageTemplateSubclassing
+
 
 _default_options = {}
 
@@ -43,11 +44,11 @@ class StringIO(list):
             self.append(value)
 
     def getvalue(self):
-        return u''.join(self)
+        return ''.join(self)
 
 
 @implementer(IPageTemplateSubclassing)
-class PageTemplate(object):
+class PageTemplate:
     """
     Page Templates using TAL, TALES, and METAL.
 
@@ -151,16 +152,16 @@ class PageTemplate(object):
         """Adjust the string type to the type of text"""
         if isinstance(
                 text,
-                six.binary_type) and not isinstance(
+                bytes) and not isinstance(
                 string,
-                six.binary_type):
+                bytes):
             return string.encode('utf-8')
 
         if isinstance(
                 text,
-                six.text_type) and not isinstance(
+                str) and not isinstance(
                 string,
-                six.text_type):
+                str):
             return string.decode('utf-8')
 
         return string
@@ -169,7 +170,7 @@ class PageTemplate(object):
         # We accept both, since the text can either come from a file (and the
         # parser will take care of the encoding) or from a TTW template, in
         # which case we already have unicode.
-        assert isinstance(text, (six.string_types, six.binary_type))
+        assert isinstance(text, (str, bytes))
 
         def bs(s):
             """Bytes or str"""
@@ -209,9 +210,8 @@ class PageTemplate(object):
                            (self._error_start, "%s: %s" %
                             sys.exc_info()[:2])) + self._text)
 
-        return bs('%s\n %s\n-->\n' % (self._error_start,
-                                      '\n'.join(self._v_errors))) + \
-            self._text
+        return bs('{}\n {}\n-->\n{}'.format(
+            self._error_start, '\n'.join(self._v_errors), self._text))
 
     def pt_source_file(self):
         """To be overridden."""
@@ -243,7 +243,7 @@ class PageTemplate(object):
             try:
                 self._v_errors = [
                     "Compilation failed",
-                    "%s.%s: %s" % (etype.__module__, etype.__name__, e)
+                    "{}.{}: {}".format(etype.__module__, etype.__name__, e)
                 ]
             finally:
                 del e
@@ -258,7 +258,7 @@ class PTRuntimeError(RuntimeError):
 
 @implementer(IPageTemplateProgram)
 @provider(IPageTemplateEngine)
-class PageTemplateEngine(object):
+class PageTemplateEngine:
     """
     Page template engine that uses the TAL interpreter to render.
 
@@ -270,7 +270,7 @@ class PageTemplateEngine(object):
         self.program = program
 
     def __call__(self, context, macros, **options):
-        output = StringIO(u'')
+        output = StringIO('')
         interpreter = TALInterpreter(
             self.program, macros, context,
             stream=output, **options
@@ -294,7 +294,7 @@ class PageTemplateEngine(object):
 
 
 # @implementer(ITracebackSupplement)
-class PageTemplateTracebackSupplement(object):
+class PageTemplateTracebackSupplement:
 
     def __init__(self, pt, namespace):
         self.manageable_object = pt
diff --git a/src/zope/pagetemplate/pagetemplatefile.py b/src/zope/pagetemplate/pagetemplatefile.py
index abbea81..b5a0a91 100644
--- a/src/zope/pagetemplate/pagetemplatefile.py
+++ b/src/zope/pagetemplate/pagetemplatefile.py
@@ -18,13 +18,14 @@ Zope object encapsulating a Page Template from the filesystem.
 
 __all__ = ("PageTemplateFile",)
 
+import logging
 import os
-import sys
 import re
-import logging
+import sys
 
 from zope.pagetemplate.pagetemplate import PageTemplate
 
+
 logger = logging.getLogger(__name__)
 
 DEFAULT_ENCODING = "utf-8"
diff --git a/src/zope/pagetemplate/tests/batch.py b/src/zope/pagetemplate/tests/batch.py
index b6cb872..c63d6b8 100644
--- a/src/zope/pagetemplate/tests/batch.py
+++ b/src/zope/pagetemplate/tests/batch.py
@@ -15,7 +15,7 @@
 """
 
 
-class batch(object):
+class batch:
     """Create a sequence batch"""
 
     def __init__(self, sequence, size, start=0, end=0,
diff --git a/src/zope/pagetemplate/tests/test_basictemplate.py b/src/zope/pagetemplate/tests/test_basictemplate.py
index 014dc74..5b421c5 100644
--- a/src/zope/pagetemplate/tests/test_basictemplate.py
+++ b/src/zope/pagetemplate/tests/test_basictemplate.py
@@ -15,10 +15,11 @@
 """
 import unittest
 
-from zope.pagetemplate.tests import util
-import zope.pagetemplate.pagetemplate
 import zope.component.testing
 
+import zope.pagetemplate.pagetemplate
+from zope.pagetemplate.tests import util
+
 
 class BasicTemplateTests(unittest.TestCase):
 
@@ -82,17 +83,18 @@ class BasicTemplateTests(unittest.TestCase):
         output = self.t.pt_render({})
         self.assertEqual(output, 'foo')
 
-        from zope.pagetemplate.interfaces import IPageTemplateEngine
         from zope.component import provideUtility
 
-        class DummyProgram(object):
+        from zope.pagetemplate.interfaces import IPageTemplateEngine
+
+        class DummyProgram:
             def __init__(self, *args):
                 self.args = args
 
             def __call__(self, *args, **kwargs):
                 return self.args, (self,) + args, kwargs
 
-        class DummyEngine(object):
+        class DummyEngine:
             @staticmethod
             def cook(*args):
                 return DummyProgram(*args), "macros"
@@ -204,7 +206,7 @@ class BasicTemplateTests(unittest.TestCase):
         self.t()
 
     def test_unicode_html(self):
-        text = u'<p>\xe4\xf6\xfc\xdf</p>'
+        text = '<p>\xe4\xf6\xfc\xdf</p>'
 
         # test with HTML parser
         self.t.pt_edit(text, 'text/html')
@@ -230,7 +232,7 @@ class BasicTemplateTests(unittest.TestCase):
         self.assertEqual(e[0], 'Macro expansion failed')
 
     def test_convert(self):
-        string = u'binary'
+        string = 'binary'
         text = b'binary'
         self.assertEqual(text, self.t._convert(string, text))
 
@@ -264,7 +266,7 @@ class BasicTemplateTests(unittest.TestCase):
 class TestPageTemplateTracebackSupplement(unittest.TestCase):
 
     def test_errors_old_style(self):
-        class PT(object):
+        class PT:
             def pt_errors(self, ns):
                 return (ns,)
 
@@ -274,7 +276,7 @@ class TestPageTemplateTracebackSupplement(unittest.TestCase):
         self.assertEqual(pts.warnings, ['ns'])
 
     def test_errors_none(self):
-        class PT(object):
+        class PT:
             def pt_errors(self, ns, check_macro_expansion=False):
                 return None
 
diff --git a/src/zope/pagetemplate/tests/test_engine.py b/src/zope/pagetemplate/tests/test_engine.py
index 0caeb93..946cfba 100644
--- a/src/zope/pagetemplate/tests/test_engine.py
+++ b/src/zope/pagetemplate/tests/test_engine.py
@@ -16,9 +16,11 @@
 import doctest
 import re
 import unittest
-import zope.pagetemplate.engine
-from zope.testing.renormalizing import RENormalizing
+
 from zope.component.testing import PlacelessSetup
+from zope.testing.renormalizing import RENormalizing
+
+import zope.pagetemplate.engine
 
 
 class EngineTests(PlacelessSetup,
@@ -43,13 +45,20 @@ class EngineTests(PlacelessSetup,
         self.assertEqual(ctx.getValue('context'), 4)
 
 
-class DummyEngine(object):
+class DummyEngine:
 
     def getTypes(self):
         return {}
 
+    def getCompilerError(self):
+        # This is only here to get meaningful errors if RestrictedPython denies
+        # execution of some code.
+        def get_error(text):  # pragma: no cover
+            raise RuntimeError(text)  # pragma: no cover
+        return get_error  # pragma: no cover
 
-class DummyContext(object):
+
+class DummyContext:
 
     _engine = DummyEngine()
 
@@ -73,8 +82,9 @@ class ZopePythonExprTests(unittest.TestCase):
     @unittest.skipUnless(zope.pagetemplate.engine.HAVE_UNTRUSTED,
                          "Needs untrusted")
     def test_forbidden_module_name(self):
-        from zope.pagetemplate.engine import ZopePythonExpr
         from zope.security.interfaces import Forbidden
+
+        from zope.pagetemplate.engine import ZopePythonExpr
         expr = ZopePythonExpr('python', '__import__("sys").exit',
                               DummyEngine())
         self.assertRaises(Forbidden, expr, DummyContext())
@@ -139,8 +149,8 @@ class TestZopeContext(PlacelessSetup,
 
     def test_evaluate_interpreter_found(self):
         get = zope.pagetemplate.engine._get_iinterpreter
-        from zope import interface
         from zope import component
+        from zope import interface
 
         class IInterpreter(interface.Interface):
             pass
@@ -149,7 +159,7 @@ class TestZopeContext(PlacelessSetup,
             return IInterpreter
 
         @interface.implementer(IInterpreter)
-        class Interpreter(object):
+        class Interpreter:
             def evaluateRawCode(self, code, globs):
                 globs['new'] = code
                 return 42
@@ -198,15 +208,9 @@ class TestAppPT(unittest.TestCase):
 def test_suite():
 
     checker = RENormalizing([
-        # Python 3 includes module name in exceptions
-        (re.compile(r"zope.security.interfaces.ForbiddenAttribute"),
-         "ForbiddenAttribute"),
-        (re.compile(r"<class 'zope.security._proxy._Proxy'>"),
-         "<type 'zope.security._proxy._Proxy'>"),
-        (re.compile(r"<class 'list'>"), "<type 'list'>"),
         # PyPy/pure-Python implementation
         (re.compile(r"<class 'zope.security.proxy.ProxyPy'>"),
-         "<type 'zope.security._proxy._Proxy'>"),
+         "<class 'zope.security._proxy._Proxy'>"),
     ])
 
     suite = unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/pagetemplate/tests/test_htmltests.py b/src/zope/pagetemplate/tests/test_htmltests.py
index 80f6c0b..de08f17 100644
--- a/src/zope/pagetemplate/tests/test_htmltests.py
+++ b/src/zope/pagetemplate/tests/test_htmltests.py
@@ -15,11 +15,11 @@
 """
 import unittest
 
-from zope.pagetemplate.tests import util
 from zope.pagetemplate.pagetemplate import PageTemplate
+from zope.pagetemplate.tests import util
 
 
-class Folder(object):
+class Folder:
     context = property(lambda self: self)
 
 
diff --git a/src/zope/pagetemplate/tests/test_ptfile.py b/src/zope/pagetemplate/tests/test_ptfile.py
index ee7fd0d..7e62111 100644
--- a/src/zope/pagetemplate/tests/test_ptfile.py
+++ b/src/zope/pagetemplate/tests/test_ptfile.py
@@ -17,11 +17,10 @@ import os
 import tempfile
 import unittest
 
-import six
 from zope.pagetemplate.pagetemplatefile import PageTemplateFile
 
 
-class AbstractPTCase(object):
+class AbstractPTCase:
 
     def get_pt(self, text=b'<html />'):
         with tempfile.NamedTemporaryFile(mode='wb', delete=False) as f:
@@ -142,11 +141,11 @@ class TypeSniffingTestCase(AbstractPTCase,
             b"\xd0\xa2\xd0\xb5\xd1\x81\xd1\x82"
             b"</title></head></html>")
         rendered = pt()
-        self.assertTrue(isinstance(rendered, six.text_type))
+        self.assertTrue(isinstance(rendered, str))
         self.assertEqual(rendered.strip(),
-                         (u"<html><head><title>"
-                          u"\u0422\u0435\u0441\u0442"
-                          u"</title></head></html>"))
+                         ("<html><head><title>"
+                          "\u0422\u0435\u0441\u0442"
+                          "</title></head></html>"))
 
     def test_html_encoding_by_meta(self):
         pt = self.get_pt(
@@ -157,11 +156,11 @@ class TypeSniffingTestCase(AbstractPTCase,
             b' content="text/html; charset=windows-1251">'
             b"</head></html>")
         rendered = pt()
-        self.assertTrue(isinstance(rendered, six.text_type))
+        self.assertTrue(isinstance(rendered, str))
         self.assertEqual(rendered.strip(),
-                         (u"<html><head><title>"
-                          u"\u0422\u0435\u0441\u0442"
-                          u"</title></head></html>"))
+                         ("<html><head><title>"
+                          "\u0422\u0435\u0441\u0442"
+                          "</title></head></html>"))
 
     def test_xhtml(self):
         pt = self.get_pt(
@@ -172,11 +171,11 @@ class TypeSniffingTestCase(AbstractPTCase,
             b' content="text/html; charset=windows-1251"/>'
             b"</head></html>")
         rendered = pt()
-        self.assertTrue(isinstance(rendered, six.text_type))
+        self.assertTrue(isinstance(rendered, str))
         self.assertEqual(rendered.strip(),
-                         (u"<html><head><title>"
-                          u"\u0422\u0435\u0441\u0442"
-                          u"</title></head></html>"))
+                         ("<html><head><title>"
+                          "\u0422\u0435\u0441\u0442"
+                          "</title></head></html>"))
 
 
 class TestPageTemplateFile(AbstractPTCase,
diff --git a/src/zope/pagetemplate/tests/util.py b/src/zope/pagetemplate/tests/util.py
index 55dbebd..1e18d23 100644
--- a/src/zope/pagetemplate/tests/util.py
+++ b/src/zope/pagetemplate/tests/util.py
@@ -13,15 +13,16 @@
 ##############################################################################
 """Utilities
 """
-from __future__ import print_function
+
 import os
 import re
 import sys
 import unittest
+
 import zope.pagetemplate.tests
 
 
-class arg(object):
+class arg:
     __allow_access_to_unprotected_subobjects__ = 1
 
     def __init__(self, nn, aa):
@@ -31,7 +32,7 @@ class arg(object):
         return str(self.arg)
 
 
-class argv(object):
+class argv:
     __allow_access_to_unprotected_subobjects__ = 1
 
     def __init__(self, argv=None):
@@ -43,14 +44,7 @@ class argv(object):
     context = property(lambda self: self)
 
 
-class _Test(unittest.TestCase):
-
-    def runTest(self):  # pragma: no cover 2.7 compatibility
-        return
-
-
-_assertEqual = _Test().assertEqual
-del _Test
+_assertEqual = unittest.TestCase().assertEqual
 
 
 def check_html(s1, s2):
@@ -85,11 +79,11 @@ output_dir = os.path.join(here, 'output')
 
 def read_input(filename):
     filename = os.path.join(input_dir, filename)
-    with open(filename, 'r') as f:
+    with open(filename) as f:
         return f.read()
 
 
 def read_output(filename):
     filename = os.path.join(output_dir, filename)
-    with open(filename, 'r') as f:
+    with open(filename) as f:
         return f.read()
diff --git a/tox.ini b/tox.ini
index 77c9b01..9f935b5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,14 +4,11 @@
 minversion = 3.18
 envlist =
     lint
-    py27
-    py35
-    py36
     py37
     py38
     py39
     py310
-    pypy
+    py311
     pypy3
     docs
     coverage
@@ -21,7 +18,7 @@ usedevelop = true
 deps =
 commands =
     zope-testrunner --test-path=src {posargs:-vc}
-    !py27-!pypy: sphinx-build -b doctest -d {envdir}/.cache/doctrees docs {envdir}/.cache/doctest
+    sphinx-build -b doctest -d {envdir}/.cache/doctrees docs {envdir}/.cache/doctest
 extras =
     test
     docs
@@ -29,15 +26,26 @@ extras =
 [testenv:lint]
 basepython = python3
 skip_install = true
+commands =
+    isort --check-only --diff {toxinidir}/src {toxinidir}/setup.py
+    flake8 src setup.py
+    check-manifest
+    check-python-versions
 deps =
-    flake8
     check-manifest
     check-python-versions >= 0.19.1
     wheel
+    flake8
+    isort
+
+[testenv:isort-apply]
+basepython = python3
+skip_install = true
+commands_pre =
+deps =
+    isort
 commands =
-    flake8 src setup.py
-    check-manifest
-    check-python-versions
+    isort {toxinidir}/src {toxinidir}/setup.py []
 
 [testenv:docs]
 basepython = python3
@@ -53,17 +61,15 @@ allowlist_externals =
     mkdir
 deps =
     coverage
-    coverage-python-version
 commands =
     mkdir -p {toxinidir}/parts/htmlcov
     coverage run -m zope.testrunner --test-path=src {posargs:-vc}
     coverage run -a -m sphinx -b doctest -d {envdir}/.cache/doctrees docs {envdir}/.cache/doctest
-    coverage html
-    coverage report -m --fail-under=97
+    coverage html --ignore-errors
+    coverage report --ignore-errors --show-missing --fail-under=97
 
 [coverage:run]
 branch = True
-plugins = coverage_python_version
 source = zope.pagetemplate
 
 [coverage:report]