Merge ~cjwatson/lazr.config:update-python-versions into lazr.config:main

[Colin Watson]

Update Python versions

Add support for Python 3.9 and 3.10. Drop support for Python 3.4.

[Jürgen Gmach (jugmac00)]

LGTM - unrelated to this MP, but could you please additionally drop 2.6 from setup.py?

review: Approve

[Colin Watson (cjwatson)]

Thanks for noticing that! Done, along with some other bits and pieces that were only for 2.6.

[Jürgen Gmach (jugmac00)]

🚀

review: Approve

diff --git a/NEWS.rst b/NEWS.rst
index d7a814b..6d56a48 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -8,6 +8,8 @@ NEWS for lazr.config
 - Publish Documentation on Read the Docs.
 - Apply inclusive naming via the woke pre-commit hook.
 - Test using ``zope.testrunner`` rather than ``nose``.
+- Officially add support for Python 3.9 and 3.10.
+- Drop support for Python 2.6 and 3.4.
 
 2.2.3 (2021-01-26)
 ==================
diff --git a/setup.py b/setup.py
index b51bef1..201f7eb 100755
--- a/setup.py
+++ b/setup.py
@@ -59,14 +59,14 @@ files. The format supports schema validation.
         "License :: OSI Approved :: GNU Library or Lesser General Public License (LGPL)",
         "Operating System :: OS Independent",
         'Programming Language :: Python',
-        'Programming Language :: Python :: 2.6',
         '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 :: 3.8',
+        'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
         ],
     extras_require=dict(
         docs=['Sphinx'],
diff --git a/src/lazr/config/interfaces.py b/src/lazr/config/interfaces.py
index 0b8a497..203ff7d 100644
--- a/src/lazr/config/interfaces.py
+++ b/src/lazr/config/interfaces.py
@@ -85,7 +85,6 @@ class ConfigErrors(ConfigSchemaError):
         :param message: a message string
         :param errors: a list of errors in the config, or None
         """
-        # Without the suppression above, this produces a warning in Python 2.6.
         self.message = message
         self.errors = errors
 
diff --git a/src/lazr/config/tests/test_config.py b/src/lazr/config/tests/test_config.py
index fa2e232..8a572b6 100644
--- a/src/lazr/config/tests/test_config.py
+++ b/src/lazr/config/tests/test_config.py
@@ -49,10 +49,6 @@ from lazr.config.interfaces import (
 
 
 class TestConfig(unittest.TestCase):
-    def setUp(self):
-        # Python 2.6 does not have assertMultilineEqual
-        self.meq = getattr(self, 'assertMultiLineEqual', self.assertEqual)
-
     def _testfile(self, conf_file):
         return pkg_resources.resource_filename(
             'lazr.config.tests.testdata', conf_file)
@@ -198,7 +194,7 @@ key1: schema suffixes are not permitted
 multiline value 1
     multiline value 2"""
         new = convert(orig)
-        self.meq(new, orig)
+        self.assertMultiLineEqual(new, orig)
 
     def test_multiline_strips_leading_and_trailing_whitespace(self):
         schema = ImplicitTypeSchema(self._testfile('base.conf'))
@@ -209,12 +205,12 @@ multiline value 1
     multiline value 2
     """
         new = convert(orig)
-        self.meq(new, orig.strip())
+        self.assertMultiLineEqual(new, orig.strip())
 
     def test_multiline_key(self):
         schema = ImplicitTypeSchema(self._testfile('base.conf'))
         config = schema.load(self._testfile('local.conf'))
-        self.meq(config['section_33'].key2, """\
+        self.assertMultiLineEqual(config['section_33'].key2, """\
 multiline value 1
 multiline value 2""")
 
diff --git a/tox.ini b/tox.ini
index 24f5373..cdc0a8c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,11 +1,12 @@
 [tox]
 envlist =
     py27
-    py34
     py35
     py36
     py37
     py38
+    py39
+    py310
     coverage
 skip_missing_interpreters = True