Created small infrastructure that makes testing some aspects of zeo

servers much easier. This was easier than I expected. I should have
done this a long time ago. :)

src/ZEO/tests/servertesting.py

+##############################################################################
+#
+# Copyright Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+# Testing the current ZEO implementation is rather hard due to the
+# architecture, which mixes concerns, especially between application
+# and networking.  Still, it's not as bad as it could be.
+
+# The 2 most important classes in the architecture are ZEOStorage and
+# StorageServer. A ZEOStorage is created for each client connection.
+# The StorageServer maintains data shared or needed for coordination
+# among clients.
+
+# The other important part of the architecture is connections.
+# Connections are used by ZEOStorages to send messages or return data
+# to clients.
+
+# Here, we'll try to provide some testing infrastructure to isolate
+# servers from the network.
+
+import ZEO.StorageServer
+import ZEO.zrpc.connection
+import ZEO.zrpc.error
+
+class StorageServer(ZEO.StorageServer.StorageServer):
+
+    def DispatcherClass(*args, **kw):
+        pass
+
+class Conection:
+
+    peer_protocol_version = ZEO.zrpc.connection.Connection.current_protocol
+    connected = True
+
+    def __init__(self, name='connection', addr='test-addr'):
+        self.name = name
+        self.addr = addr
+
+    def close(self):
+        print self.name, 'closed'
+        self.connected = False
+
+    def poll(self):
+        if not self.connected:
+            raise ZEO.zrpc.error.DisconnectedError()
+
+    def callAsync(self, meth, *args):
+        print self.name, 'callAsync', meth, repr(args)