Config with pure python (#28)

* Lint the code.
* Add support for Python 3.9.

23 files changed, 365 insertions, 340 deletions

diff --git a/.coveragerc b/.coveragerc
deleted file mode 100644
index a644d51..0000000
--- a/.coveragerc
+++ /dev/null
@@ -1,11 +0,0 @@
-[run]
-source = zope.pagetemplate
-
-[report]
-precision = 2
-exclude_lines =
-    pragma: no cover
-    if __name__ == '__main__':
-    raise NotImplementedError
-    self.fail
-    raise AssertionError
diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..f3e46f5
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,39 @@
+# Generated from:
+# https://github.com/zopefoundation/meta/tree/master/config/pure-python
+#
+# EditorConfig Configuration file, for more details see:
+# http://EditorConfig.org
+# EditorConfig is a convention description, that could be interpreted
+# by multiple editors to enforce common coding conventions for specific
+# file types
+
+# top-most EditorConfig file:
+# Will ignore other EditorConfig files in Home directory or upper tree level.
+root = true
+
+
+[*]  # For All Files
+# Unix-style newlines with a newline ending every file
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+# Set default charset
+charset = utf-8
+# Indent style default
+indent_style = space
+# Max Line Length - a hard line wrap, should be disabled
+max_line_length = off
+
+[*.{py,cfg,ini}]
+# 4 space indentation
+indent_size = 4
+
+[*.{yml,zpt,pt,dtml}]
+# 2 space indentation
+indent_size = 2
+
+[{Makefile,.gitmodules}]
+# Tab indentation (no size specified, but view as 4 spaces)
+indent_style = tab
+indent_size = unset
+tab_width = unset
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000..38cb0de
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,61 @@
+# Generated from:
+# https://github.com/zopefoundation/meta/tree/master/config/pure-python
+name: tests
+
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: '0 12 * * 0'  # run once a week on Sunday
+  # Allow to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+  build:
+    strategy:
+      # We want to see all failures:
+      fail-fast: false
+      matrix:
+        config:
+        # [Python version, tox env]
+        - ["3.8",   "lint"]
+        - ["2.7",   "py27"]
+        - ["3.5",   "py35"]
+        - ["3.6",   "py36"]
+        - ["3.7",   "py37"]
+        - ["3.8",   "py38"]
+        - ["3.9",   "py39"]
+        - ["pypy2", "pypy"]
+        - ["pypy3", "pypy3"]
+        - ["3.8",   "docs"]
+        - ["3.8",   "coverage"]
+
+    runs-on: ubuntu-latest
+    name: ${{ matrix.config[1] }}
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.config[0] }}
+    - name: Pip cache
+      uses: actions/cache@v2
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ matrix.config[0] }}-${{ hashFiles('setup.*', 'tox.ini') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-${{ matrix.config[0] }}-
+          ${{ runner.os }}-pip-
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install tox
+    - name: Test
+      run: tox -e ${{ matrix.config[1] }}
+    - name: Coverage
+      if: matrix.config[1] == 'coverage'
+      run: |
+        pip install coveralls coverage-python-version
+        coveralls --service=github
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.gitignore b/.gitignore
index aa19a47..9a9e9b9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,17 +1,29 @@
+# Generated from:
+# https://github.com/zopefoundation/meta/tree/master/config/pure-python
+*.egg-info/
+*.profraw
 *.pyc
-*.so
-*.dll
-__pycache__
-src/*.egg-info
-
+*.pyo
+.coverage
+.coverage.*
+.eggs/
 .installed.cfg
-.tox
+.mr.developer.cfg
+.tox/
+.vscode/
+__pycache__/
 bin/
 build/
+coverage.xml
 develop-eggs/
+develop/
+dist/
+docs/_build
 eggs/
+etc/
+lib/
+lib64
+log/
 parts/
-dist/
-.coverage
-htmlcov/
-docs/_build/
+pyvenv.cfg
+var/
diff --git a/.meta.toml b/.meta.toml
new file mode 100644
index 0000000..fcc59a1
--- /dev/null
+++ b/.meta.toml
@@ -0,0 +1,25 @@
+# Generated from:
+# https://github.com/zopefoundation/meta/tree/master/config/pure-python
+[meta]
+template = "pure-python"
+commit-id = "785810f9b7cf459f84c3b1a45eb2d639bfb666d2"
+
+[python]
+with-appveyor = false
+with-pypy = true
+with-legacy-python = true
+with-docs = true
+with-sphinx-doctests = true
+
+[tox]
+use-flake8 = true
+
+[coverage]
+fail-under = 97
+
+[manifest]
+additional-rules = [
+    "recursive-include docs *.bat",
+    "recursive-include docs *.pt",
+    "recursive-include src *.html",
+    ]
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 9df35c7..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,21 +0,0 @@
-language: python
-python:
-    - 2.7
-    - 3.5
-    - 3.6
-    - 3.7
-    - 3.8
-    - pypy
-    - pypy3
-install:
-    - pip install -U pip setuptools
-    - pip install -U coverage coveralls
-    - pip install -U -e .[test,docs]
-script:
-    - coverage run -m zope.testrunner --test-path=src
-    - coverage run -a -m sphinx -b doctest -d docs/_build/doctrees docs docs/_build/doctest
-after_success:
-    - coveralls
-notifications:
-    email: false
-cache: pip
diff --git a/CHANGES.rst b/CHANGES.rst
index 169dfda..68808c3 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -7,6 +7,8 @@
 
 - Avoid traceback reference cycle in ``PageTemplate._cook``.
 
+- Add support for Python 3.9.
+
 
 4.5.0 (2020-02-10)
 ==================
diff --git a/MANIFEST.in b/MANIFEST.in
index 0fde81c..8a3cd9b 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,15 +1,16 @@
+# Generated from:
+# https://github.com/zopefoundation/meta/tree/master/config/pure-python
 include *.rst
 include *.txt
-include bootstrap.py
 include buildout.cfg
 include tox.ini
-include .travis.yml
-include .coveragerc
 
-recursive-include src *.txt *.html *.pt
-
-recursive-include docs *.rst
 recursive-include docs *.py
-recursive-include docs *.pt
+recursive-include docs *.rst
+recursive-include docs *.txt
 recursive-include docs Makefile
+
+recursive-include src *.py
 recursive-include docs *.bat
+recursive-include docs *.pt
+recursive-include src *.html
diff --git a/bootstrap.py b/bootstrap.py
deleted file mode 100644
index a459921..0000000
--- a/bootstrap.py
+++ /dev/null
@@ -1,210 +0,0 @@
-##############################################################################
-#
-# Copyright (c) 2006 Zope Foundation and Contributors.
-# All Rights Reserved.
-#
-# This software is subject to the provisions of the Zope Public License,
-# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
-# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
-# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
-# FOR A PARTICULAR PURPOSE.
-#
-##############################################################################
-"""Bootstrap a buildout-based project
-
-Simply run this script in a directory containing a buildout.cfg.
-The script accepts buildout command-line options, so you can
-use the -c option to specify an alternate configuration file.
-"""
-
-import os
-import shutil
-import sys
-import tempfile
-
-from optparse import OptionParser
-
-__version__ = '2015-07-01'
-# See zc.buildout's changelog if this version is up to date.
-
-tmpeggs = tempfile.mkdtemp(prefix='bootstrap-')
-
-usage = '''\
-[DESIRED PYTHON FOR BUILDOUT] bootstrap.py [options]
-
-Bootstraps a buildout-based project.
-
-Simply run this script in a directory containing a buildout.cfg, using the
-Python that you want bin/buildout to use.
-
-Note that by using --find-links to point to local resources, you can keep
-this script from going over the network.
-'''
-
-parser = OptionParser(usage=usage)
-parser.add_option("--version",
-                  action="store_true", default=False,
-                  help=("Return bootstrap.py version."))
-parser.add_option("-t", "--accept-buildout-test-releases",
-                  dest='accept_buildout_test_releases',
-                  action="store_true", default=False,
-                  help=("Normally, if you do not specify a --version, the "
-                        "bootstrap script and buildout gets the newest "
-                        "*final* versions of zc.buildout and its recipes and "
-                        "extensions for you.  If you use this flag, "
-                        "bootstrap and buildout will get the newest releases "
-                        "even if they are alphas or betas."))
-parser.add_option("-c", "--config-file",
-                  help=("Specify the path to the buildout configuration "
-                        "file to be used."))
-parser.add_option("-f", "--find-links",
-                  help=("Specify a URL to search for buildout releases"))
-parser.add_option("--allow-site-packages",
-                  action="store_true", default=False,
-                  help=("Let bootstrap.py use existing site packages"))
-parser.add_option("--buildout-version",
-                  help="Use a specific zc.buildout version")
-parser.add_option("--setuptools-version",
-                  help="Use a specific setuptools version")
-parser.add_option("--setuptools-to-dir",
-                  help=("Allow for re-use of existing directory of "
-                        "setuptools versions"))
-
-options, args = parser.parse_args()
-if options.version:
-    print("bootstrap.py version %s" % __version__)
-    sys.exit(0)
-
-
-######################################################################
-# load/install setuptools
-
-try:
-    from urllib.request import urlopen
-except ImportError:
-    from urllib2 import urlopen
-
-ez = {}
-if os.path.exists('ez_setup.py'):
-    exec(open('ez_setup.py').read(), ez)
-else:
-    exec(urlopen('https://bootstrap.pypa.io/ez_setup.py').read(), ez)
-
-if not options.allow_site_packages:
-    # ez_setup imports site, which adds site packages
-    # this will remove them from the path to ensure that incompatible versions
-    # of setuptools are not in the path
-    import site
-    # inside a virtualenv, there is no 'getsitepackages'.
-    # We can't remove these reliably
-    if hasattr(site, 'getsitepackages'):
-        for sitepackage_path in site.getsitepackages():
-            # Strip all site-packages directories from sys.path that
-            # are not sys.prefix; this is because on Windows
-            # sys.prefix is a site-package directory.
-            if sitepackage_path != sys.prefix:
-                sys.path[:] = [x for x in sys.path
-                               if sitepackage_path not in x]
-
-setup_args = dict(to_dir=tmpeggs, download_delay=0)
-
-if options.setuptools_version is not None:
-    setup_args['version'] = options.setuptools_version
-if options.setuptools_to_dir is not None:
-    setup_args['to_dir'] = options.setuptools_to_dir
-
-ez['use_setuptools'](**setup_args)
-import setuptools
-import pkg_resources
-
-# This does not (always?) update the default working set.  We will
-# do it.
-for path in sys.path:
-    if path not in pkg_resources.working_set.entries:
-        pkg_resources.working_set.add_entry(path)
-
-######################################################################
-# Install buildout
-
-ws = pkg_resources.working_set
-
-setuptools_path = ws.find(
-    pkg_resources.Requirement.parse('setuptools')).location
-
-# Fix sys.path here as easy_install.pth added before PYTHONPATH
-cmd = [sys.executable, '-c',
-       'import sys; sys.path[0:0] = [%r]; ' % setuptools_path +
-       'from setuptools.command.easy_install import main; main()',
-       '-mZqNxd', tmpeggs]
-
-find_links = os.environ.get(
-    'bootstrap-testing-find-links',
-    options.find_links or
-    ('http://downloads.buildout.org/'
-     if options.accept_buildout_test_releases else None)
-    )
-if find_links:
-    cmd.extend(['-f', find_links])
-
-requirement = 'zc.buildout'
-version = options.buildout_version
-if version is None and not options.accept_buildout_test_releases:
-    # Figure out the most recent final version of zc.buildout.
-    import setuptools.package_index
-    _final_parts = '*final-', '*final'
-
-    def _final_version(parsed_version):
-        try:
-            return not parsed_version.is_prerelease
-        except AttributeError:
-            # Older setuptools
-            for part in parsed_version:
-                if (part[:1] == '*') and (part not in _final_parts):
-                    return False
-            return True
-
-    index = setuptools.package_index.PackageIndex(
-        search_path=[setuptools_path])
-    if find_links:
-        index.add_find_links((find_links,))
-    req = pkg_resources.Requirement.parse(requirement)
-    if index.obtain(req) is not None:
-        best = []
-        bestv = None
-        for dist in index[req.project_name]:
-            distv = dist.parsed_version
-            if _final_version(distv):
-                if bestv is None or distv > bestv:
-                    best = [dist]
-                    bestv = distv
-                elif distv == bestv:
-                    best.append(dist)
-        if best:
-            best.sort()
-            version = best[-1].version
-if version:
-    requirement = '=='.join((requirement, version))
-cmd.append(requirement)
-
-import subprocess
-if subprocess.call(cmd) != 0:
-    raise Exception(
-        "Failed to execute command:\n%s" % repr(cmd)[1:-1])
-
-######################################################################
-# Import and run buildout
-
-ws.add_entry(tmpeggs)
-ws.require(requirement)
-import zc.buildout.buildout
-
-if not [a for a in args if '=' not in a]:
-    args.append('bootstrap')
-
-# if -c was provided, we push it back into args for buildout' main function
-if options.config_file is not None:
-    args[0:0] = ['-c', options.config_file]
-
-zc.buildout.buildout.main(args)
-shutil.rmtree(tmpeggs)
diff --git a/setup.cfg b/setup.cfg
index 2a9acf1..8b04203 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,2 +1,14 @@
+# Generated from:
+# https://github.com/zopefoundation/meta/tree/master/config/pure-python
 [bdist_wheel]
 universal = 1
+
+[flake8]
+doctests = 1
+
+[check-manifest]
+ignore =
+    .editorconfig
+    .meta.toml
+    docs/_build/html/_sources/*
+    docs/_build/doctest/*
diff --git a/setup.py b/setup.py
index 155cf99..72131e7 100644
--- a/setup.py
+++ b/setup.py
@@ -58,6 +58,7 @@ setup(name='zope.pagetemplate',
           'Programming Language :: Python :: 3.6',
           'Programming Language :: Python :: 3.7',
           'Programming Language :: Python :: 3.8',
+          'Programming Language :: Python :: 3.9',
           'Programming Language :: Python :: Implementation :: CPython',
           'Programming Language :: Python :: Implementation :: PyPy',
           'Natural Language :: English',
@@ -99,4 +100,4 @@ setup(name='zope.pagetemplate',
       include_package_data=True,
       zip_safe=False,
       tests_require=TESTS_REQUIRE,
-)
+      )
diff --git a/src/zope/__init__.py b/src/zope/__init__.py
index de40ea7..656dc0f 100644
--- a/src/zope/__init__.py
+++ b/src/zope/__init__.py
@@ -1 +1 @@
-__import__('pkg_resources').declare_namespace(__name__)
+__import__('pkg_resources').declare_namespace(__name__)  # pragma: no cover
diff --git a/src/zope/pagetemplate/engine.py b/src/zope/pagetemplate/engine.py
index fc2a0cd..4eb805d 100644
--- a/src/zope/pagetemplate/engine.py
+++ b/src/zope/pagetemplate/engine.py
@@ -29,19 +29,21 @@ from zope.traversing.adapters import traversePathElement
 from zope.security.proxy import ProxyFactory, removeSecurityProxy
 from zope.i18n import translate
 
-try:
+try:  # pragma: no cover
+    # Until https://github.com/zopefoundation/zope.untrustedpython/issues/2
+    # is fixed Python 3 does not support special handling for untrusted code:
     from zope.untrustedpython import rcompile
     from zope.untrustedpython.builtins import SafeBuiltins
     HAVE_UNTRUSTED = True
-except ImportError: # pragma: no cover
+except ImportError:
     HAVE_UNTRUSTED = False
 
-# PyPy doesn't support assigning to '__builtins__', even when
-# using eval() (http://pypy.readthedocs.org/en/latest/cpython_differences.html),
-# so don't try to use it. It won't work.
-if HAVE_UNTRUSTED:
+# PyPy doesn't support assigning to '__builtins__', even when using eval()
+# (http://pypy.readthedocs.org/en/latest/cpython_differences.html), so don't
+# try to use it. It won't work.
+if HAVE_UNTRUSTED:  # pragma: no cover
     import platform
-    if platform.python_implementation() == 'PyPy': # pragma: no cover
+    if platform.python_implementation() == 'PyPy':
         HAVE_UNTRUSTED = False
         del rcompile
         del SafeBuiltins
@@ -53,9 +55,11 @@ from zope.tales.tales import ExpressionEngine, Context
 
 from zope.pagetemplate.i18n import ZopeMessageFactory as _
 
+
 class InlineCodeError(Exception):
     pass
 
+
 class ZopeTraverser(object):
 
     def __init__(self, proxify=None):
@@ -85,15 +89,19 @@ class ZopeTraverser(object):
             object = self.proxify(object)
         return object
 
+
 zopeTraverser = ZopeTraverser(ProxyFactory)
 
+
 class ZopePathExpr(PathExpr):
 
     def __init__(self, name, expr, engine):
         super(ZopePathExpr, self).__init__(name, expr, engine, zopeTraverser)
 
+
 trustedZopeTraverser = ZopeTraverser()
 
+
 class TrustedZopePathExpr(PathExpr):
 
     def __init__(self, name, expr, engine):
@@ -118,9 +126,11 @@ class ZopePythonExpr(PythonExpr):
         def _compile(self, text, filename):
             return rcompile.compile(text, filename, 'eval')
 
+
 def _get_iinterpreter():
     from zope.app.interpreter.interfaces import IInterpreter
-    return IInterpreter # pragma: no cover
+    return IInterpreter  # pragma: no cover
+
 
 class ZopeContextBase(Context):
     """Base class for both trusted and untrusted evaluation contexts."""
@@ -173,7 +183,10 @@ class ZopeContext(ZopeContextBase):
         >>> from zope.pagetemplate.engine import ZopeContext
         >>> from zope.tales.tales import ExpressionEngine
         >>> from zope.security.proxy import ProxyFactory
-        >>> output = [('version', 'xxx'), ('mode', 'html'), ('other', 'things')]
+        >>> output = [
+        ...     ('version', 'xxx'),
+        ...     ('mode', 'html'),
+        ...     ('other', 'things')]
         >>> def expression(context):
         ...     return ProxyFactory(output)
         ...
@@ -305,6 +318,7 @@ class ZopeBaseEngine(ExpressionEngine):
 
         return context
 
+
 class ZopeEngine(ZopeBaseEngine):
     """
     Untrusted expression engine.
@@ -439,6 +453,7 @@ class ZopeEngine(ZopeBaseEngine):
         return ProxyFactory(
             super(ZopeEngine, self).getFunctionNamespace(namespacename))
 
+
 class TrustedZopeEngine(ZopeBaseEngine):
     """
     Trusted expression engine.
@@ -498,6 +513,7 @@ def _Engine(engine=None):
 
     return engine
 
+
 def _TrustedEngine(engine=None):
     if engine is None:
         engine = TrustedZopeEngine()
@@ -506,6 +522,7 @@ def _TrustedEngine(engine=None):
     engine.registerBaseName('modules', TraversableModuleImporter())
     return engine
 
+
 def _create_base_engine(engine, pathtype):
     for pt in pathtype._default_type_names:
         engine.registerType(pt, pathtype)
diff --git a/src/zope/pagetemplate/interfaces.py b/src/zope/pagetemplate/interfaces.py
index 9a0fe71..0812a83 100644
--- a/src/zope/pagetemplate/interfaces.py
+++ b/src/zope/pagetemplate/interfaces.py
@@ -50,14 +50,15 @@ class IPageTemplate(Interface):
         """Get the template source
         """
 
-    macros = Attribute("An object that implements the ``__getitem__`` "
-                       "protocol (e.g., a :class:`dict`), containing page template macros.")
+    macros = Attribute(
+        "An object that implements the ``__getitem__`` "
+        "protocol (e.g., a :class:`dict`), containing page template macros.")
+
 
 class IPageTemplateSubclassing(IPageTemplate):
     """Behavior that may be overridden or used by subclasses
     """
 
-
     def pt_getContext(**kw):
         """Compute a dictionary of top-level template names
 
@@ -136,13 +137,14 @@ class IPageTemplateProgram(Interface):
 
         Optional arguments:
 
-        :keyword bool debug: enable debugging output to sys.stderr (off by default).
-        :keyword int wrap: try to wrap attributes on opening tags to this number of
-            column (default: 60).
+        :keyword bool debug: enable debugging output to sys.stderr (off by
+            default).
+        :keyword int wrap: try to wrap attributes on opening tags to this
+            number of column (default: 60).
         :keyword bool metal: enable METAL macro processing (on by default).
         :keyword bool tal: enable TAL processing (on by default).
-        :keyword int showtal: do not strip away TAL directives.  A special value of
-            -1 (which is the default setting) enables showtal when TAL
+        :keyword int showtal: do not strip away TAL directives.  A special
+            value of -1 (which is the default setting) enables showtal when TAL
             processing is disabled, and disables showtal when TAL processing is
             enabled.  Note that you must use 0, 1, or -1; true boolean values
             are not supported (for historical reasons).
@@ -151,6 +153,6 @@ class IPageTemplateProgram(Interface):
             Note that Zope turns this value off by default.
         :keyword int stackLimit: set macro nesting limit (default: 100).
         :keyword bool i18nInterpolate: enable i18n translations (default: on).
-        :keyword bool sourceAnnotations: enable source annotations with HTML comments
-            (default: off).
+        :keyword bool sourceAnnotations: enable source annotations with HTML
+            comments (default: off).
         """
diff --git a/src/zope/pagetemplate/pagetemplate.py b/src/zope/pagetemplate/pagetemplate.py
index 78d4d50..bd9eafb 100644
--- a/src/zope/pagetemplate/pagetemplate.py
+++ b/src/zope/pagetemplate/pagetemplate.py
@@ -72,7 +72,7 @@ class PageTemplate(object):
         Calls pt_getContext() to construct the top-level namespace
         passed to the TALES expression engine, then calls pt_render()
         to perform the rendering.
-    """
+    """  # noqa: E501 line too long
 
     _error_start = '<!-- Page Template Diagnostics'
     _error_end = '-->'
@@ -103,7 +103,7 @@ class PageTemplate(object):
                 'options': options,
                 'args': args,
                 'nothing': None,
-        }
+                }
         rval.update(self.pt_getEngine().getBaseNames())
         return rval
 
@@ -123,7 +123,7 @@ class PageTemplate(object):
 
         __traceback_supplement__ = (
             PageTemplateTracebackSupplement, self, namespace
-            )
+        )
 
         if self._v_errors:
             raise PTRuntimeError(str(self._v_errors))
@@ -133,7 +133,7 @@ class PageTemplate(object):
         return self._v_program(
             context, self._v_macros, tal=not source, showtal=showtal,
             strictinsert=0, sourceAnnotations=sourceAnnotations
-            )
+        )
 
     def pt_errors(self, namespace, check_macro_expansion=True):
         self._cook_check()
@@ -144,14 +144,23 @@ class PageTemplate(object):
             try:
                 self.pt_render(namespace, source=1)
             except Exception:
-                return ('Macro expansion failed', '%s: %s' % sys.exc_info()[:2])
+                return (
+                    'Macro expansion failed', '%s: %s' % sys.exc_info()[:2])
 
     def _convert(self, string, text):
         """Adjust the string type to the type of text"""
-        if isinstance(text, six.binary_type) and not isinstance(string, six.binary_type):
+        if isinstance(
+                text,
+                six.binary_type) and not isinstance(
+                string,
+                six.binary_type):
             return string.encode('utf-8')
 
-        if isinstance(text, six.text_type) and not isinstance(string, six.text_type):
+        if isinstance(
+                text,
+                six.text_type) and not isinstance(
+                string,
+                six.text_type):
             return string.decode('utf-8')
 
         return string
@@ -182,6 +191,7 @@ class PageTemplate(object):
     def read(self, request=None):
         """Gets the source, sometimes with macros expanded."""
         self._cook_check()
+
         def bs(s):
             """Bytes or str"""
             return self._convert(s, self._text)
@@ -194,14 +204,14 @@ class PageTemplate(object):
                 # this point, since we are not evaluating the template.
                 context = self.pt_getContext(self, request)
                 return self.pt_render(context, source=1)
-            except:
+            except BaseException:
                 return (bs('%s\n Macro expansion failed\n %s\n-->\n' %
-                           (self._error_start, "%s: %s" % sys.exc_info()[:2])) +
-                        self._text)
+                           (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
+            self._text
 
     def pt_source_file(self):
         """To be overridden."""
@@ -225,16 +235,16 @@ class PageTemplate(object):
         try:
             engine = queryUtility(
                 IPageTemplateEngine, default=PageTemplateEngine
-                )
+            )
             self._v_program, self._v_macros = engine.cook(
                 source_file, self._text, pt_engine, self.content_type)
-        except:
+        except BaseException:
             etype, e = sys.exc_info()[:2]
             try:
                 self._v_errors = [
                     "Compilation failed",
                     "%s.%s: %s" % (etype.__module__, etype.__name__, e)
-                    ]
+                ]
             finally:
                 del e
 
@@ -252,10 +262,10 @@ class PageTemplateEngine(object):
     """
     Page template engine that uses the TAL interpreter to render.
 
-    This class implements :class:`zope.pagetemplate.interfaces.IPageTemplateProgram`.
+    This class implements
+    :class:`zope.pagetemplate.interfaces.IPageTemplateProgram`.
     """
 
-
     def __init__(self, program):
         self.program = program
 
@@ -264,7 +274,7 @@ class PageTemplateEngine(object):
         interpreter = TALInterpreter(
             self.program, macros, context,
             stream=output, **options
-            )
+        )
         interpreter()
         return output.getvalue()
 
@@ -283,7 +293,7 @@ class PageTemplateEngine(object):
         return cls(program), macros
 
 
-#@implementer(ITracebackSupplement)
+# @implementer(ITracebackSupplement)
 class PageTemplateTracebackSupplement(object):
 
     def __init__(self, pt, namespace):
diff --git a/src/zope/pagetemplate/pagetemplatefile.py b/src/zope/pagetemplate/pagetemplatefile.py
index 4cf0bf3..abbea81 100644
--- a/src/zope/pagetemplate/pagetemplatefile.py
+++ b/src/zope/pagetemplate/pagetemplatefile.py
@@ -34,10 +34,12 @@ meta_pattern = re.compile(
     br'\s+content=["\']?([^;]+);\s*charset=([^"\']+)["\']?\s*/?\s*>\s*',
     re.IGNORECASE)
 
+
 def package_home(gdict):
     filename = gdict["__file__"]
     return os.path.dirname(filename)
 
+
 class PageTemplateFile(PageTemplate):
     "Zope wrapper for filesystem Page Template using TAL, TALES, and METAL"
 
@@ -109,6 +111,7 @@ class PageTemplateFile(PageTemplate):
     def __getstate__(self):
         raise TypeError("non-picklable object")
 
+
 XML_PREFIXES = [
     b"<?xml",                      # ascii, utf-8
     b"\xef\xbb\xbf<?xml",          # utf-8 w/ byte order mark
@@ -116,10 +119,11 @@ XML_PREFIXES = [
     b"<\0?\0x\0m\0l\0",            # utf-16 little endian
     b"\xfe\xff\0<\0?\0x\0m\0l",    # utf-16 big endian w/ byte order mark
     b"\xff\xfe<\0?\0x\0m\0l\0",    # utf-16 little endian w/ byte order mark
-    ]
+]
 
 XML_PREFIX_MAX_LENGTH = max(map(len, XML_PREFIXES))
 
+
 def sniff_type(text):
     """Return 'text/xml' if text appears to be XML, otherwise return None."""
     for prefix in XML_PREFIXES:
diff --git a/src/zope/pagetemplate/tests/batch.py b/src/zope/pagetemplate/tests/batch.py
index 5d193bd..b6cb872 100644
--- a/src/zope/pagetemplate/tests/batch.py
+++ b/src/zope/pagetemplate/tests/batch.py
@@ -14,6 +14,7 @@
 """Batching support tests
 """
 
+
 class batch(object):
     """Create a sequence batch"""
 
@@ -38,14 +39,14 @@ class batch(object):
         return self._first
 
     def next_sequence_end_item(self):
-        _start, end, _spam = opt(self._end+1-self._overlap, 0,
+        _start, end, _spam = opt(self._end + 1 - self._overlap, 0,
                                  self._size, self._orphan, self._sequence)
-        return self._sequence[end-1]
+        return self._sequence[end - 1]
 
     def next_sequence_start_item(self):
-        start, _end, _spam = opt(self._end+1-self._overlap, 0,
+        start, _end, _spam = opt(self._end + 1 - self._overlap, 0,
                                  self._size, self._orphan, self._sequence)
-        return self._sequence[start-1]
+        return self._sequence[start - 1]
 
     def next_sequence(self):
         return self._end < len(self._sequence)
@@ -58,6 +59,7 @@ class batch(object):
             raise IndexError(index)
         return self._sequence[index + self._first]
 
+
 def opt(start, end, size, orphan, sequence):
     assert size >= 1
     assert start > 0
diff --git a/src/zope/pagetemplate/tests/test_basictemplate.py b/src/zope/pagetemplate/tests/test_basictemplate.py
index f998f21..014dc74 100644
--- a/src/zope/pagetemplate/tests/test_basictemplate.py
+++ b/src/zope/pagetemplate/tests/test_basictemplate.py
@@ -19,6 +19,7 @@ from zope.pagetemplate.tests import util
 import zope.pagetemplate.pagetemplate
 import zope.component.testing
 
+
 class BasicTemplateTests(unittest.TestCase):
 
     def setUp(self):
@@ -117,7 +118,7 @@ class BasicTemplateTests(unittest.TestCase):
             'showtal': False,
             'sourceAnnotations': False,
             'strictinsert': 0,
-            })
+        })
 
     def test_batches_and_formatting(self):
         # DTML test 3: batches and formatting:
@@ -234,7 +235,11 @@ class BasicTemplateTests(unittest.TestCase):
         self.assertEqual(text, self.t._convert(string, text))
 
     def test_write_error(self):
-        self.t.write(self.t._error_start + 'stuff' + self.t._error_end + self.t._newline)
+        self.t.write(
+            self.t._error_start +
+            'stuff' +
+            self.t._error_end +
+            self.t._newline)
         self.assertEqual(self.t._text, '')
 
     def test_read_no_expand(self):
@@ -263,7 +268,8 @@ class TestPageTemplateTracebackSupplement(unittest.TestCase):
             def pt_errors(self, ns):
                 return (ns,)
 
-        pts = zope.pagetemplate.pagetemplate.PageTemplateTracebackSupplement(PT(), 'ns')
+        pts = zope.pagetemplate.pagetemplate.PageTemplateTracebackSupplement(
+            PT(), 'ns')
 
         self.assertEqual(pts.warnings, ['ns'])
 
@@ -272,5 +278,6 @@ class TestPageTemplateTracebackSupplement(unittest.TestCase):
             def pt_errors(self, ns, check_macro_expansion=False):
                 return None
 
-        pts = zope.pagetemplate.pagetemplate.PageTemplateTracebackSupplement(PT(), 'ns')
+        pts = zope.pagetemplate.pagetemplate.PageTemplateTracebackSupplement(
+            PT(), 'ns')
         self.assertEqual(pts.warnings, [])
diff --git a/src/zope/pagetemplate/tests/test_engine.py b/src/zope/pagetemplate/tests/test_engine.py
index 97ec8f6..0caeb93 100644
--- a/src/zope/pagetemplate/tests/test_engine.py
+++ b/src/zope/pagetemplate/tests/test_engine.py
@@ -20,6 +20,7 @@ import zope.pagetemplate.engine
 from zope.testing.renormalizing import RENormalizing
 from zope.component.testing import PlacelessSetup
 
+
 class EngineTests(PlacelessSetup,
                   unittest.TestCase):
 
@@ -41,11 +42,13 @@ class EngineTests(PlacelessSetup,
         self.assertEqual(ctx.getValue('request'), 3)
         self.assertEqual(ctx.getValue('context'), 4)
 
+
 class DummyEngine(object):
 
     def getTypes(self):
         return {}
 
+
 class DummyContext(object):
 
     _engine = DummyEngine()
@@ -53,6 +56,7 @@ class DummyContext(object):
     def __init__(self, **kw):
         self.vars = kw
 
+
 class ZopePythonExprTests(unittest.TestCase):
 
     def test_simple(self):
@@ -86,8 +90,12 @@ class ZopePythonExprTests(unittest.TestCase):
 class TestZopeContext(PlacelessSetup,
                       unittest.TestCase):
 
-    assertRaisesRegex = getattr(unittest.TestCase, 'assertRaisesRegex',
-                                getattr(unittest.TestCase, 'assertRaisesRegexp'))
+    assertRaisesRegex = getattr(
+        unittest.TestCase,
+        'assertRaisesRegex',
+        getattr(
+            unittest.TestCase,
+            'assertRaisesRegexp'))
 
     def _makeOne(self):
         return zope.pagetemplate.engine.ZopeContext(None, {})
@@ -111,8 +119,10 @@ class TestZopeContext(PlacelessSetup,
     def test_evaluate_interpreter_not_found(self):
         get = zope.pagetemplate.engine._get_iinterpreter
         from zope import interface
+
         class IInterpreter(interface.Interface):
             pass
+
         def mock_get():
             return IInterpreter
 
@@ -120,8 +130,9 @@ class TestZopeContext(PlacelessSetup,
         ctx.evaluateInlineCode = True
         zope.pagetemplate.engine._get_iinterpreter = mock_get
         try:
-            with self.assertRaisesRegex(zope.pagetemplate.engine.InlineCodeError,
-                                        "No interpreter named"):
+            with self.assertRaisesRegex(
+                    zope.pagetemplate.engine.InlineCodeError,
+                    "No interpreter named"):
                 ctx.evaluateCode('lang', 'code')
         finally:
             zope.pagetemplate.engine._get_iinterpreter = get
@@ -130,8 +141,10 @@ class TestZopeContext(PlacelessSetup,
         get = zope.pagetemplate.engine._get_iinterpreter
         from zope import interface
         from zope import component
+
         class IInterpreter(interface.Interface):
             pass
+
         def mock_get():
             return IInterpreter
 
@@ -167,7 +180,6 @@ class TestTraversableModuleImporter(unittest.TestCase):
         with self.assertRaises(TraversalError):
             tmi.traverse('zope.pagetemplate.engine.DNE', ())
 
-
         with self.assertRaises(TraversalError):
             tmi.traverse('pickle.no_sub_module', ())
 
@@ -201,7 +213,3 @@ def test_suite():
     suite.addTest(doctest.DocTestSuite('zope.pagetemplate.engine',
                                        checker=checker))
     return suite
-
-
-if __name__ == '__main__':
-    unittest.main(defaultTest='test_suite')
diff --git a/src/zope/pagetemplate/tests/test_htmltests.py b/src/zope/pagetemplate/tests/test_htmltests.py
index 1550634..80f6c0b 100644
--- a/src/zope/pagetemplate/tests/test_htmltests.py
+++ b/src/zope/pagetemplate/tests/test_htmltests.py
@@ -22,6 +22,7 @@ from zope.pagetemplate.pagetemplate import PageTemplate
 class Folder(object):
     context = property(lambda self: self)
 
+
 class HTMLTests(unittest.TestCase):
 
     def setUp(self):
@@ -58,7 +59,6 @@ class HTMLTests(unittest.TestCase):
         out = t(laf=self.folder.laf, getProducts=self.getProducts)
         util.check_html(expect, out)
 
-
     def test_3(self):
         self.folder.laf.write(util.read_input('teeshoplaf.html'))
 
@@ -153,5 +153,6 @@ class HTMLTests(unittest.TestCase):
         errors = t.pt_errors(namespace, check_macro_expansion=False)
         self.assertFalse(errors)
 
+
 def test_suite():
     return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/pagetemplate/tests/test_ptfile.py b/src/zope/pagetemplate/tests/test_ptfile.py
index e5cc2e9..ee7fd0d 100644
--- a/src/zope/pagetemplate/tests/test_ptfile.py
+++ b/src/zope/pagetemplate/tests/test_ptfile.py
@@ -20,6 +20,7 @@ import unittest
 import six
 from zope.pagetemplate.pagetemplatefile import PageTemplateFile
 
+
 class AbstractPTCase(object):
 
     def get_pt(self, text=b'<html />'):
@@ -30,6 +31,7 @@ class AbstractPTCase(object):
         pt.read()
         return pt
 
+
 class TypeSniffingTestCase(AbstractPTCase,
                            unittest.TestCase):
 
@@ -189,7 +191,6 @@ class TestPageTemplateFile(AbstractPTCase,
                               _prefix=os.path.dirname(__file__))
         self.assertEqual(pt.filename, __file__)
 
-
     def test_cook_no_debug(self):
         pt = self.get_pt()
         pt._v_debug = False
@@ -199,11 +200,11 @@ class TestPageTemplateFile(AbstractPTCase,
         pt._cook_check()
         self.assertEqual(lr, pt._v_last_read)
 
-
     def test_cook_mtime_fails(self):
         pt = self.get_pt()
 
         getmtime = os.path.getmtime
+
         def bad(_path):
             raise OSError()
         os.path.getmtime = bad
diff --git a/src/zope/pagetemplate/tests/util.py b/src/zope/pagetemplate/tests/util.py
index 5ef2ad3..55dbebd 100644
--- a/src/zope/pagetemplate/tests/util.py
+++ b/src/zope/pagetemplate/tests/util.py
@@ -20,6 +20,7 @@ import sys
 import unittest
 import zope.pagetemplate.tests
 
+
 class arg(object):
     __allow_access_to_unprotected_subobjects__ = 1
 
@@ -29,6 +30,7 @@ class arg(object):
     def __str__(self):
         return str(self.arg)
 
+
 class argv(object):
     __allow_access_to_unprotected_subobjects__ = 1
 
@@ -40,29 +42,35 @@ class argv(object):
 
     context = property(lambda self: self)
 
+
 class _Test(unittest.TestCase):
 
-    def runTest(self): # pragma: no cover 2.7 compatibility
+    def runTest(self):  # pragma: no cover 2.7 compatibility
         return
 
+
 _assertEqual = _Test().assertEqual
 del _Test
 
+
 def check_html(s1, s2):
     s1 = normalize_html(s1)
     s2 = normalize_html(s2)
     _assertEqual(s1, s2, "HTML Output Changed")
 
+
 def check_xml(s1, s2):
     s1 = normalize_xml(s1)
     s2 = normalize_xml(s2)
     _assertEqual(s1, s2, 'XML Output Changed')
 
+
 def normalize_html(s):
     s = re.sub(r"[ \t]+", " ", s)
     s = re.sub(r"/>", ">", s)
     return s
 
+
 def normalize_xml(s):
     s = re.sub(r"\s+", " ", s)
     s = re.sub(r"(?s)\s+<", "<", s)
@@ -70,17 +78,17 @@ def normalize_xml(s):
     return s
 
 
-
-
 here = os.path.dirname(zope.pagetemplate.tests.__file__)
 input_dir = os.path.join(here, 'input')
 output_dir = os.path.join(here, 'output')
 
+
 def read_input(filename):
     filename = os.path.join(input_dir, filename)
     with open(filename, 'r') as f:
         return f.read()
 
+
 def read_output(filename):
     filename = os.path.join(output_dir, filename)
     with open(filename, 'r') as f:
diff --git a/tox.ini b/tox.ini
index 3132873..bbaa8d6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,33 +1,87 @@
+# Generated from:
+# https://github.com/zopefoundation/meta/tree/master/config/pure-python
 [tox]
+minversion = 3.18
 envlist =
-   py27,py35,py36,py37,py38,pypy,pypy3,coverage,docs
+    lint
+    py27
+    py35
+    py36
+    py37
+    py38
+    py39
+    pypy
+    pypy3
+    docs
+    coverage
 
 [testenv]
+usedevelop = true
+deps =
+    zope.testrunner
+    # Until repoze.sphinx.autointerface supports Sphinx 4.x we cannot use it:
+    Sphinx < 4
 commands =
-    zope-testrunner --test-path=src []
-    sphinx-build -b doctest -d {envdir}/doctrees docs {envdir}/doctest
-deps=
-    py27,pypy: Sphinx < 2
-    py27,pypy: sphinxcontrib-websupport < 1.2
+    zope-testrunner --test-path=src {posargs:-vc}
+    sphinx-build -b doctest -d {envdir}/.cache/doctrees docs {envdir}/.cache/doctest
 extras =
     test
     docs
 
-[testenv:coverage]
-usedevelop = true
-basepython =
-    python3.7
-commands =
-    coverage run -m zope.testrunner --test-path=src []
-    coverage run -a -m sphinx -b doctest -d {envdir}/.cache/doctrees docs {envdir}/.cache/doctest
-    coverage html
-    coverage report --fail-under=100
+[testenv:lint]
+basepython = python3
+skip_install = true
 deps =
-    coverage
+    flake8
+    check-manifest
+    check-python-versions
+commands =
+    flake8 src setup.py
+    check-manifest
+    check-python-versions
 
 [testenv:docs]
-basepython =
-    python3.7
+basepython = python3
+skip_install = false
+# Until repoze.sphinx.autointerface supports Sphinx 4.x we cannot use it:
+deps = Sphinx < 4
+commands_pre =
 commands =
     sphinx-build -b html -d docs/_build/doctrees docs docs/_build/html
     sphinx-build -b doctest -d docs/_build/doctrees docs docs/_build/doctest
+
+[testenv:coverage]
+basepython = python3
+allowlist_externals =
+    mkdir
+deps =
+    coverage
+    coverage-python-version
+    # Until repoze.sphinx.autointerface supports Sphinx 4.x we cannot use it:
+    Sphinx < 4
+    zope.testrunner
+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:run]
+branch = True
+plugins = coverage_python_version
+source = src
+
+[coverage:report]
+precision = 2
+exclude_lines =
+    pragma: no cover
+    pragma: nocover
+    except ImportError:
+    raise NotImplementedError
+    if __name__ == '__main__':
+    self.fail
+    raise AssertionError
+
+[coverage:html]
+directory = parts/htmlcov