Use python-modernize to make py code Python 3 compatible

[takluyver]

As discussed in #133.

This still passes the tests with Python 2, but I can't work out how to test with Python 3 - running ant -Dpython=python3 test hangs at this point:

test_tether_word_count.py
Modules: 'test_datafile','test_datafile','test_io','test_ipc','test_protocol','test_schema','test_script','test_tether_task','test_tether_task_runner','test_tether_word_count'
Non-null modules arg. creating script
pythonpath: /home/takluyver/Code/avro/lang/py/build/src:/home/takluyver/Code/avro/lang/py/build/test:/home/takluyver/Code/avro/lang/py/build/lib

[manu-chroma]

Hey @takluyver, I checked out your branch and copied tests/ directory from py3 folder to py2/src/avro/ and invoked python run_tests.py inside the tests/ directory. All tests are passing. I'm not sure if there are other Python 3 tests which are invoked by ant

(venv3) [venv3] ~/github/avro/lang/py/src/avro/tests $ python run_tests.py                                                                                                                                                            23:23:11
...............................2017-07-04 23:23:15,261 INFO test_ipc.py:118 : Echo RPC Server listening on 127.0.0.1:46881
2017-07-04 23:23:15,261 INFO test_ipc.py:119 : RPC socket: <socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 46881)>
2017-07-04 23:23:15,261 INFO ipc.py:179 : Sending handshake request: {'serverHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85', 'clientHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85'}
2017-07-04 23:23:15,262 INFO ipc.py:204 : writing request: {'ping': {'timestamp': 31415, 'text': 'hello ping'}}
2017-07-04 23:23:15,262 INFO ipc.py:654 : Serialized request: b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85\x00\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85\x00\x00\x08ping\xee\xea\x03\x14hello ping'
2017-07-04 23:23:15,263 INFO ipc.py:412 : Processing handshake request: {'meta': None, 'clientProtocol': None, 'serverHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85', 'clientHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85'}
2017-07-04 23:23:15,263 INFO ipc.py:441 : Handshake response: {'match': 'BOTH'}
2017-07-04 23:23:15,263 INFO ipc.py:375 : Processing request: {'ping': {'timestamp': 31415, 'text': 'hello ping'}}
2017-07-04 23:23:15,263 INFO test_ipc.py:90 : Message: {"request": [{"type": {"type": "record", "namespace": "org.apache.avro.ipc.echo", "name": "Ping", "fields": [{"type": "long", "name": "timestamp", "default": -1}, {"type": "string", "name": "text", "default": ""}]}, "name": "ping"}], "errors": [], "response": {"type": "record", "namespace": "org.apache.avro.ipc.echo", "name": "Pong", "fields": [{"type": "long", "name": "timestamp", "default": -1}, {"type": "org.apache.avro.ipc.echo.Ping", "name": "ping"}]}}
2017-07-04 23:23:15,263 INFO test_ipc.py:91 : Request: {'ping': {'timestamp': 31415, 'text': 'hello ping'}}
2017-07-04 23:23:15,264 INFO ipc.py:656 : Serialized response: b'\x00\x00\x00\x00\x00\x00\x80\xf0\xe0\xeb\xa1W\xee\xea\x03\x14hello ping'
127.0.0.1 - - [04/Jul/2017 23:23:15] "POST / HTTP/1.1" 200 -
2017-07-04 23:23:15,264 INFO ipc.py:665 : Response sent
2017-07-04 23:23:15,264 INFO ipc.py:219 : Processing handshake response: {'serverHash': None, 'match': 'BOTH', 'serverProtocol': None, 'meta': None}
2017-07-04 23:23:15,265 INFO test_ipc.py:143 : Received echo response: {'ping': {'timestamp': 31415, 'text': 'hello ping'}, 'timestamp': 1499190795264}
2017-07-04 23:23:15,265 INFO ipc.py:179 : Sending handshake request: {'serverHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85', 'clientHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85'}
2017-07-04 23:23:15,265 INFO ipc.py:204 : writing request: {'ping': {'timestamp': 123456, 'text': 'hello again'}}
2017-07-04 23:23:15,266 INFO ipc.py:654 : Serialized request: b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85\x00\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85\x00\x00\x08ping\x80\x89\x0f\x16hello again'
2017-07-04 23:23:15,266 INFO ipc.py:412 : Processing handshake request: {'meta': None, 'clientProtocol': None, 'serverHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85', 'clientHash': b'\xce\x8a<\x94i\x95\xabb*\x81\xf3\xa4t\x99;\x85'}
2017-07-04 23:23:15,266 INFO ipc.py:441 : Handshake response: {'match': 'BOTH'}
2017-07-04 23:23:15,266 INFO ipc.py:375 : Processing request: {'ping': {'timestamp': 123456, 'text': 'hello again'}}
2017-07-04 23:23:15,266 INFO test_ipc.py:90 : Message: {"request": [{"type": {"type": "record", "namespace": "org.apache.avro.ipc.echo", "name": "Ping", "fields": [{"type": "long", "name": "timestamp", "default": -1}, {"type": "string", "name": "text", "default": ""}]}, "name": "ping"}], "errors": [], "response": {"type": "record", "namespace": "org.apache.avro.ipc.echo", "name": "Pong", "fields": [{"type": "long", "name": "timestamp", "default": -1}, {"type": "org.apache.avro.ipc.echo.Ping", "name": "ping"}]}}
2017-07-04 23:23:15,266 INFO test_ipc.py:91 : Request: {'ping': {'timestamp': 123456, 'text': 'hello again'}}
2017-07-04 23:23:15,267 INFO ipc.py:656 : Serialized response: b'\x00\x00\x00\x00\x00\x00\x84\xf0\xe0\xeb\xa1W\x80\x89\x0f\x16hello again'
127.0.0.1 - - [04/Jul/2017 23:23:15] "POST / HTTP/1.1" 200 -
2017-07-04 23:23:15,267 INFO ipc.py:665 : Response sent
2017-07-04 23:23:15,267 INFO ipc.py:219 : Processing handshake response: {'serverHash': None, 'match': 'BOTH', 'serverProtocol': None, 'meta': None}
2017-07-04 23:23:15,267 INFO test_ipc.py:149 : Received echo response: {'ping': {'timestamp': 123456, 'text': 'hello again'}, 'timestamp': 1499190795266}
...................
----------------------------------------------------------------------
Ran 50 tests in 2.114s

OK

[takluyver]

There's a lang/py/test directory containing tests - they seem to be invoked by running ant test, and they work for Python 2, but get stuck when I try with Py3.