still support py27

src/wormhole_transit_relay/test/test_rlimits.py

@@ -1,5 +1,8 @@
 from __future__ import print_function, unicode_literals
-from unittest import mock
+try:
+    from unittest import mock
+except ImportError:
+    import mock
 from twisted.trial import unittest
 from ..increase_rlimits import increase_rlimits
 

src/wormhole_transit_relay/test/test_service.py

@@ -1,6 +1,9 @@
 from __future__ import unicode_literals, print_function
 from twisted.trial import unittest
-from unittest import mock
+try:
+    from unittest import mock
+except ImportError:
+    import mock
 from twisted.application.service import MultiService
 from .. import server_tap
 

src/wormhole_transit_relay/test/test_stats.py

@@ -1,6 +1,9 @@
 from __future__ import print_function, unicode_literals
 import os, io, json, sqlite3
-from unittest import mock
+try:
+    from unittest import mock
+except ImportError:
+    import mock
 from twisted.trial import unittest
 from ..transit_server import Transit
 from .. import database