get tests to work on py2.7

only install 'noiseprotocol' (which is necessary for dilation to work) if the
"dilate" feature is requested (e.g. `pip install magic-wormhole[dilate]`)

setup.py

@@ -48,13 +48,13 @@ setup(name="magic-wormhole",
           "click",
           "humanize",
           "txtorcon >= 18.0.2", # 18.0.2 fixes py3.4 support
-          "noiseprotocol",
       ],
       extras_require={
           ':sys_platform=="win32"': ["pywin32"],
           "dev": ["mock", "tox", "pyflakes",
                   "magic-wormhole-transit-relay==0.1.2",
                   "magic-wormhole-mailbox-server==0.3.1"],
+          "dilate": ["noiseprotocol"],
       },
       test_suite="wormhole.test",
       cmdclass=commands,

src/wormhole/_dilation/_noise.py

@@ -0,0 +1,11 @@
+try:
+    from noise.exceptions import NoiseInvalidMessage
+except ImportError:
+    class NoiseInvalidMessage(Exception):
+        pass
+
+try:
+    from noise.connection import NoiseConnection
+except ImportError:
+    # allow imports to work on py2.7, even if dilation doesn't
+    NoiseConnection = None

src/wormhole/_dilation/connection.py

@@ -12,6 +12,7 @@ from .._interfaces import IDilationConnector
 from ..observer import OneShotObserver
 from .encode import to_be4, from_be4
 from .roles import FOLLOWER
+from ._noise import NoiseInvalidMessage
 
 # InboundFraming is given data and returns Frames (Noise wire-side
 # bytestrings). It handles the relay handshake and the prologue. The Frames it
@@ -346,7 +347,6 @@ class _Record(object):
 
     @n.output()
     def process_handshake(self, frame):
-        from noise.exceptions import NoiseInvalidMessage
         try:
             payload = self._noise.read_message(frame)
             # Noise can include unencrypted data in the handshake, but we don't
@@ -359,7 +359,6 @@ class _Record(object):
 
     @n.output()
     def decrypt_message(self, frame):
-        from noise.exceptions import NoiseInvalidMessage
         try:
             message = self._noise.decrypt(frame)
         except NoiseInvalidMessage as e:

src/wormhole/_dilation/connector.py

@@ -1,7 +1,6 @@
 from __future__ import print_function, unicode_literals
 from collections import defaultdict
 from binascii import hexlify
-import six
 from attr import attrs, attrib
 from attr.validators import instance_of, provides, optional
 from automat import MethodicalMachine
@@ -15,13 +14,14 @@ from .. import ipaddrs  # TODO: move into _dilation/
 from .._interfaces import IDilationConnector, IDilationManager
 from ..timing import DebugTiming
 from ..observer import EmptyableSet
-from ..util import HKDF
+from ..util import HKDF, to_unicode
 from .connection import DilatedConnectionProtocol, KCM
 from .roles import LEADER
 
 from .._hints import (DirectTCPV1Hint, TorTCPV1Hint, RelayV1Hint,
                       parse_hint_argv, describe_hint_obj, endpoint_from_hint_obj,
                       encode_hint)
+from ._noise import NoiseConnection
 
 
 def build_sided_relay_handshake(key, side):
@@ -37,14 +37,13 @@ PROLOGUE_FOLLOWER = b"Magic-Wormhole Dilation Handshake v1 Follower\n\n"
 NOISEPROTO = b"Noise_NNpsk0_25519_ChaChaPoly_BLAKE2s"
 
 def build_noise():
-    from noise.connection import NoiseConnection
     return NoiseConnection.from_name(NOISEPROTO)
 
 @attrs
 @implementer(IDilationConnector)
 class Connector(object):
     _dilation_key = attrib(validator=instance_of(type(b"")))
-    _transit_relay_location = attrib(validator=optional(instance_of(str)))
+    _transit_relay_location = attrib(validator=optional(instance_of(type(u""))))
     _manager = attrib(validator=provides(IDilationManager))
     _reactor = attrib()
     _eventual_queue = attrib()
@@ -265,7 +264,7 @@ class Connector(object):
             # lp is an IListeningPort
             self._listeners.add(lp)  # for shutdown and tests
             portnum = lp.getHost().port
-            direct_hints = [DirectTCPV1Hint(six.u(addr), portnum, 0.0)
+            direct_hints = [DirectTCPV1Hint(to_unicode(addr), portnum, 0.0)
                             for addr in addresses]
             self.listener_ready(direct_hints)
         d.addCallback(_listening)

src/wormhole/test/dilate/test_connector.py

@@ -7,8 +7,9 @@ from twisted.internet.task import Clock
 from twisted.internet.defer import Deferred
 from ...eventual import EventualQueue
 from ..._interfaces import IDilationManager, IDilationConnector
-from ..._dilation import roles
 from ..._hints import DirectTCPV1Hint, RelayV1Hint, TorTCPV1Hint
+from ..._dilation import roles
+from ..._dilation._noise import NoiseConnection
 from ..._dilation.connection import KCM
 from ..._dilation.connector import (Connector,
                                     build_sided_relay_handshake,
@@ -101,6 +102,8 @@ class TestConnector(unittest.TestCase):
                           ])
 
     def test_build_noise(self):
+        if not NoiseConnection:
+            raise unittest.SkipTest("noiseprotocol unavailable")
         build_noise()
 
     def test_build_protocol_leader(self):

src/wormhole/test/dilate/test_record.py

@@ -2,7 +2,7 @@ from __future__ import print_function, unicode_literals
 import mock
 from zope.interface import alsoProvides
 from twisted.trial import unittest
-from noise.exceptions import NoiseInvalidMessage
+from ..._dilation._noise import NoiseInvalidMessage
 from ..._dilation.connection import (IFramer, Frame, Prologue,
                                      _Record, Handshake,
                                      Disconnect, Ping)

src/wormhole/util.py

@@ -12,6 +12,10 @@ def HKDF(skm, outlen, salt=None, CTXinfo=b""):
 def to_bytes(u):
     return unicodedata.normalize("NFC", u).encode("utf-8")
 
+def to_unicode(any):
+    if isinstance(any, type(u"")):
+        return any
+    return any.decode("ascii")
 
 def bytes_to_hexstr(b):
     assert isinstance(b, type(b""))