Fix 3 errors in python2.7

Author: yanqd0

pytest_pylint.py

@@ -166,8 +166,8 @@ def pytest_configure(config):
     config.addinivalue_line('markers', "pylint: Tests which run pylint.")
 
 
-# pylint: disable=too-few-public-methods
-class PylintPlugin:
+# pylint: disable=too-few-public-methods, useless-object-inheritance
+class PylintPlugin(object):
     """
     A Plugin object for pylint, which loads and records file mtimes.
     """

test_pytest_pylint.py

@@ -223,20 +223,18 @@ def test_skip_checked_files(testdir):
     Test a file twice which can pass pylint.
     The 2nd time should be skipped.
     """
-    testdir.makepyfile('''#!/usr/bin/env python
-"""A hello world script."""
-
-from __future__ import print_function
-
-print('Hello world!')
-# pylint: disable=missing-final-newline
-''')
+    testdir.makepyfile(
+        '#!/usr/bin/env python',
+        '"""A hello world script."""',
+        '',
+        'from __future__ import print_function',
+        '',
+        'print("Hello world!")  # pylint: disable=missing-final-newline',
+    )
     # The 1st time should be passed
     result = testdir.runpytest('--pylint')
-    print(result.stdout.str())
     assert '1 passed' in result.stdout.str()
 
     # The 2nd time should be skipped
     result = testdir.runpytest('--pylint')
-    print(result.stdout.str())
     assert '1 skipped' in result.stdout.str()