Hi! I am learning to develop TDD way. I want to create a server that understands PB protocol. Initially I thought it would be a good idea to avoid real network connections in my tests, so I tried to use `proto_helpers.StringTransport`:
----------
import cStringIO
from twisted.spread import pb
from twisted.trial import unittest
from twisted.test import proto_helpers
class Document(pb.Root):
def remote_convert(self, props):
self.props = props
class DocTestCase(unittest.TestCase):
def setUp(self):
# set up server
self.doc = Document()
factory = pb.PBServerFactory(self.doc)
self.broker = factory.buildProtocol(('127.0.0.1', 0))
tr = proto_helpers.StringTransport()
self.broker.makeConnection(tr)
# this is what a client sends
self.props = {'name': 'MyDoc',
'path': '/path/'}
# prepare data
serialized_props = self.broker.serialize(self.props)
msg = ('message', 1, 'root', 'convert', 1,
['tuple', serialized_props], ['dictionary'])
io = cStringIO.StringIO()
self.broker._encode(msg, io.write)
self.chunk = io.getvalue()
def test_convert(self):
# data arrived
self.broker.dataReceived(self.chunk)
self.assertEqual(self.props, self.doc.props)
----------
However, `Document.remote_convert` is never executed so the test above
fails. After debugging I discovered that `Broker._encode` produces
different results depending on whether `self.broker.makeConnection(tr)` is
called or not.
And I created a test case that shows a difference. Here `test_convert1`
succeeds while `test_convert2` fails:
----------
class DocTestCase(unittest.TestCase):
def setUp(self):
self.doc = Document()
factory = pb.PBServerFactory(self.doc)
self.broker = factory.buildProtocol(('127.0.0.1', 0))
self.props = {'name': 'MyDoc',
'path': '/path/'}
serialized_props = self.broker.serialize(self.props)
self.msg = ('message', 1, 'root', 'convert', 1,
['tuple', serialized_props], ['dictionary'])
def test_convert1(self):
self.broker.currentDialect = 'pb'
self.broker.setPrefixLimit(64)
self.broker.transport = proto_helpers.StringTransport()
io = cStringIO.StringIO()
self.broker._encode(self.msg, io.write)
self.broker.dataReceived(io.getvalue())
self.assertEqual(self.props, self.doc.props)
def test_convert2(self):
self.tr = proto_helpers.StringTransport()
self.broker.makeConnection(self.tr)
io = cStringIO.StringIO()
self.broker._encode(self.msg, io.write)
self.broker.dataReceived(io.getvalue())
self.assertEqual(self.props, self.doc.props)
----------
I wonder what causes this behavior and, in general, if `StringTransport` is
suitable for testing PB protocol.
Thanks in advance. For your convenience I attached files with these test
cases.
--
with regards,
Maxim
test_pb.py
Description: Binary data
test_pb1.py
Description: Binary data
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