Standardize the sys.path fix up and fix a few pylint warnings.

tests/subprocess2_test.py

Index: tests/subprocess2_test.py
diff --git a/tests/subprocess2_test.py b/tests/subprocess2_test.py
index cb390751e2c9b47e35c7f42e5ee57394f7371e81..562d2215b1121f9a8e70449b1dd85f46fd99a593 100755
--- a/tests/subprocess2_test.py
+++ b/tests/subprocess2_test.py
@@ -17,14 +17,10 @@ try:
 except ImportError:
   fcntl = None
 
-ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-sys.path.insert(0, ROOT_DIR)
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 import subprocess2
 
-# Method could be a function
-# pylint: disable=R0201
-
 
 def convert_to_crlf(string):
   """Unconditionally convert LF to CRLF."""
@@ -84,7 +80,8 @@ class DefaultsTest(unittest.TestCase):
         assert not results
         results.update(kwargs)
         results['args'] = args
-      def communicate(self):
+      @staticmethod
+      def communicate():
         return None, None
     subprocess2.Popen = fake_Popen
     return results
@@ -98,7 +95,8 @@ class DefaultsTest(unittest.TestCase):
         assert not results
         results.update(kwargs)
         results['args'] = args
-      def communicate(self):
+      @staticmethod
+      def communicate():
         return None, None
     subprocess2.subprocess.Popen = fake_Popen
     return results