Issue 4884 - Fix test runner flake8 3.3.0, don't use flake8's deprecated API

flake8-eyeo/setup.py

 # This file is part of Adblock Plus <https://adblockplus.org/>,
 # Copyright (C) 2006-2016 Eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 
 from __future__ import print_function
 
 import os
 import glob
 import tokenize
 import sys
 import re
-
-try:
-    from StringIO import StringIO
-except ImportError:
-    from io import StringIO
+import subprocess
 
 from setuptools import setup, Command
 
 
 class TestCommand(Command):
     user_options = []
 
     def _get_expected_errors(self, filename):
         errors = set()
 
@@ skipping 11 matching lines @@
 
         with open(filename, 'rb') as file:
             if sys.version_info[0] >= 3:
                 for token in tokenize.tokenize(file.readline):
                     tokeneater(*token)
             else:
                 tokenize.tokenize(file.readline, tokeneater)
 
         return errors
 
-    def _get_reported_errors(self, filename, style_guide):
-        orig_stdout = sys.stdout
-        sys.stdout = stdout = StringIO()
+    def _get_reported_errors(self, filename):
+        output = subprocess.Popen(['flake8', filename],
+                                  stdout=subprocess.PIPE).communicate()[0]
 
-        try:
-            style_guide.check_files([filename])
-        finally:
-            sys.stdout = orig_stdout
-
-        stdout.seek(0)
         errors = set()
-
-        for line in stdout:
+        for line in output.decode('utf-8').splitlines():
             _, lineno, colno, error = line.split(':', 3)
             errors.add((int(lineno), int(colno), error.split()[0]))
 
         return errors
 
     def initialize_options(self):
         pass
 
     def finalize_options(self):
         pass
 
     def run(self):
-        try:
-            import flake8.engine as api
-        except ImportError:
-            import flake8.api.legacy as api
-
         directory = os.path.dirname(__file__)
         filenames = glob.glob(os.path.join(directory, 'tests', '*.py'))
-        style_guide = api.get_style_guide()
         failed = False
 
         for filename in sorted(filenames):
             expected = self._get_expected_errors(filename)
-            reported = self._get_reported_errors(filename, style_guide)
+            reported = self._get_reported_errors(filename)
             failures = expected ^ reported
 
             if not failures:
                 print(filename + ': OK')
                 continue
 
             for record in sorted(failures):
                 lineno, colno, error = record
 
                 print('{}:{}:{}: '.format(filename, lineno, colno), end='')
@@ skipping 15 matching lines @@
     entry_points={
         'flake8.extension': [
             'eyeo.A    = flake8_eyeo:ASTChecker',
             'eyeo.A1   = flake8_eyeo:check_quotes',
             'eyeo.A111 = flake8_eyeo:check_redundant_parenthesis',
             'eyeo.A303 = flake8_eyeo:check_non_default_encoding',
         ],
     },
     cmdclass={'test': TestCommand}
 )