Do not require mock in Python 3 in certbot-compatibility-test module (#7899)

* Do not require mock in Python 3 in certbot-compatibility-test module

* error when trying to build wheels with old setuptools

* add type: ignores

certbot-compatibility-test/certbot_compatibility_test/configurators/apache/common.py

@@ -3,7 +3,10 @@ import os
 import shutil
 import subprocess
 
-import mock
+try:
+    import mock
+except ImportError: # pragma: no cover
+    from unittest import mock # type: ignore
 import zope.interface
 
 from certbot import errors as le_errors

certbot-compatibility-test/certbot_compatibility_test/validator_test.py

@@ -1,7 +1,10 @@
 """Tests for certbot_compatibility_test.validator."""
 import unittest
 
-import mock
+try:
+    import mock
+except ImportError: # pragma: no cover
+    from unittest import mock # type: ignore
 import OpenSSL
 import requests
 

certbot-compatibility-test/setup.py

@@ -1,5 +1,7 @@
+from distutils.version import StrictVersion
 import sys
 
+from setuptools import __version__ as setuptools_version
 from setuptools import find_packages
 from setuptools import setup
 
@@ -8,12 +10,20 @@ version = '1.4.0.dev0'
 install_requires = [
     'certbot',
     'certbot-apache',
-    'mock',
     'six',
     'requests',
     'zope.interface',
 ]
 
+setuptools_known_environment_markers = (StrictVersion(setuptools_version) >= StrictVersion('36.2'))
+if setuptools_known_environment_markers:
+    install_requires.append('mock ; python_version < "3.3"')
+elif 'bdist_wheel' in sys.argv[1:]:
+    raise RuntimeError('Error, you are trying to build certbot wheels using an old version '
+                       'of setuptools. Version 36.2+ of setuptools is required.')
+elif sys.version_info < (3,3):
+    install_requires.append('mock')
+
 if sys.version_info < (2, 7, 9):
     # For secure SSL connexion with Python 2.7 (InsecurePlatformWarning)
     install_requires.append('ndg-httpsclient')