Fixed notification tests to run on Py3.

Call 2to3 on the dynamically generated scripts.

tests/test_notify.py

@@ -4,6 +4,7 @@ from testutils import unittest
 import psycopg2
 from psycopg2 import extensions
 from testconfig import dsn
+from testutils import script_to_py3
 
 import sys
 import time
@@ -52,7 +53,7 @@ conn.close()
 """
             % { 'dsn': dsn, 'sec': sec, 'name': name, 'payload': payload})
 
-        return Popen([sys.executable, '-c', script], stdout=PIPE)
+        return Popen([sys.executable, '-c', script_to_py3(script)], stdout=PIPE)
 
     def test_notifies_received_on_poll(self):
         self.autocommit(self.conn)

tests/testutils.py

@@ -4,6 +4,7 @@
 
 # Use unittest2 if available. Otherwise mock a skip facility with warnings.
 
+import os
 import sys
 
 try:
@@ -92,3 +93,23 @@ def skip_on_python3(f):
 
     return skip_on_python3_
 
+def script_to_py3(script):
+    """Convert a script to Python3 syntax if required."""
+    if sys.version_info[0] < 3:
+        return script
+
+    import tempfile
+    f = tempfile.NamedTemporaryFile(suffix=".py")
+    f.write(script.encode())
+    f.flush()
+
+    # 2to3 is way too chatty
+    import logging
+    logging.basicConfig(filename=os.devnull)
+
+    from lib2to3.main import main
+    if main("lib2to3.fixes", ['--no-diffs', '-w', '-n', f.name]):
+        raise Exception('py3 conversion failed')
+
+    return open(f.name).read()
+