twisted: split allocate_ports() out to util.py

so it can be used by downstream projects

src/wormhole/test/test_twisted.py

@@ -1,34 +1,15 @@
 import json
 from twisted.trial import unittest
-from twisted.internet import defer, protocol, endpoints, reactor
+from twisted.internet import defer
 from twisted.application import service
 from ..servers.relay import RelayServer
 from ..twisted.transcribe import SymmetricWormhole, UsageError
+from ..twisted.util import allocate_ports
 from .. import __version__
 #from twisted.python import log
 #import sys
 #log.startLogging(sys.stdout)
 
-def allocate_port():
-    ep = endpoints.serverFromString(reactor, "tcp:0:interface=127.0.0.1")
-    d = ep.listen(protocol.Factory())
-    def _listening(lp):
-        port = lp.getHost().port
-        d2 = lp.stopListening()
-        d2.addCallback(lambda _: port)
-        return d2
-    d.addCallback(_listening)
-    return d
-
-def allocate_ports():
-    d = defer.DeferredList([allocate_port(), allocate_port()])
-    def _done(results):
-        port1 = results[0][1]
-        port2 = results[1][1]
-        return (port1, port2)
-    d.addCallback(_done)
-    return d
-
 class Basic(unittest.TestCase):
     def setUp(self):
         self.sp = service.MultiService()

src/wormhole/twisted/util.py

@@ -0,0 +1,21 @@
+from twisted.internet import defer, protocol, endpoints, reactor
+
+def allocate_port():
+    ep = endpoints.serverFromString(reactor, "tcp:0:interface=127.0.0.1")
+    d = ep.listen(protocol.Factory())
+    def _listening(lp):
+        port = lp.getHost().port
+        d2 = lp.stopListening()
+        d2.addCallback(lambda _: port)
+        return d2
+    d.addCallback(_listening)
+    return d
+
+def allocate_ports():
+    d = defer.DeferredList([allocate_port(), allocate_port()])
+    def _done(results):
+        port1 = results[0][1]
+        port2 = results[1][1]
+        return (port1, port2)
+    d.addCallback(_done)
+    return d