Tests pass on both Python 2 and Python 3.

setup.py

@@ -54,7 +54,9 @@ install_requires = [
     # * foolscap >= 0.12.5 has ConnectionInfo and ReconnectionInfo
     # * foolscap >= 0.12.6 has an i2p.sam_endpoint() that takes kwargs
     # * foolscap 0.13.2 drops i2p support completely
-    "foolscap == 0.13.1",
+    # * foolscap >= 20.4 is necessary for Python 3
+    "foolscap == 0.13.1; ; python_version < '3.0'",
+    "foolscap >= 20.4.0; ; python_version > '3.0'",
 
     # * cryptography 2.6 introduced some ed25519 APIs we rely on.  Note that
     #   Twisted[conch] also depends on cryptography and Twisted[tls]

src/allmydata/test/test_humanreadable.py

@@ -6,7 +6,7 @@ from __future__ import print_function
 
 from future import standard_library
 standard_library.install_aliases()
-from builtins import *
+from past.builtins import long
 from twisted.trial import unittest
 
 from allmydata.util import humanreadable
@@ -26,8 +26,9 @@ class HumanReadable(unittest.TestCase):
         self.failUnlessEqual(hr(self.test_repr),
                              "<bound method HumanReadable.test_repr of <allmydata.test.test_humanreadable.HumanReadable testMethod=test_repr>>")
         self.failUnlessEqual(hr(long(1)), "1")
-        self.failUnlessEqual(hr(10**40),
-                             "100000000000000000...000000000000000000")
+        self.assertIn(hr(10**40),
+                      ["100000000000000000...000000000000000000",
+                       "100000000000000000...0000000000000000000"])
         self.failUnlessEqual(hr(self), "<allmydata.test.test_humanreadable.HumanReadable testMethod=test_repr>")
         self.failUnlessEqual(hr([1,2]), "[1, 2]")
         self.failUnlessEqual(hr({1:2}), "{1:2}")
@@ -50,4 +51,5 @@ class HumanReadable(unittest.TestCase):
         except Exception as e:
             self.failUnless(
                 hr(e) == "<NoArgumentException>" # python-2.4
-                or hr(e) == "NoArgumentException()") # python-2.5
+                or hr(e) == "NoArgumentException()" # python-2.5
+                or hr(e) == "<NoArgumentException: ()>", hr(e)) # python-3

src/allmydata/util/humanreadable.py

@@ -1,5 +1,12 @@
-import exceptions, os
-from repr import Repr
+from __future__ import division
+from __future__ import absolute_import
+from __future__ import print_function
+from __future__ import unicode_literals
+from future import standard_library
+standard_library.install_aliases()
+
+import os
+from reprlib import Repr
 
 class BetterRepr(Repr, object):
     def __init__(self):
@@ -14,21 +21,21 @@ class BetterRepr(Repr, object):
         self.maxother = 300
 
     def repr_function(self, obj, level):
-        if hasattr(obj, 'func_code'):
-            return '<' + obj.func_name + '() at ' + os.path.basename(obj.func_code.co_filename) + ':' + str(obj.func_code.co_firstlineno) + '>'
+        if hasattr(obj, '__code__'):
+            return '<' + obj.__name__ + '() at ' + os.path.basename(obj.__code__.co_filename) + ':' + str(obj.__code__.co_firstlineno) + '>'
         else:
-            return '<' + obj.func_name + '() at (builtin)'
+            return '<' + obj.__name__ + '() at (builtin)'
 
     def repr_instance_method(self, obj, level):
-        if hasattr(obj, 'func_code'):
-            return '<' + obj.im_class.__name__ + '.' + obj.im_func.__name__ + '() at ' + os.path.basename(obj.im_func.func_code.co_filename) + ':' + str(obj.im_func.func_code.co_firstlineno) + '>'
+        if hasattr(obj, '__code__'):
+            return '<' + obj.__self__.__class__.__name__ + '.' + obj.__func__.__name__ + '() at ' + os.path.basename(obj.__func__.__code__.co_filename) + ':' + str(obj.__func__.__code__.co_firstlineno) + '>'
         else:
-            return '<' + obj.im_class.__name__ + '.' + obj.im_func.__name__ + '() at (builtin)'
+            return '<' + obj.__self__.__class__.__name__ + '.' + obj.__func__.__name__ + '() at (builtin)'
 
     def repr_long(self, obj, level):
         s = repr(obj) # XXX Hope this isn't too slow...
         if len(s) > self.maxlong:
-            i = max(0, (self.maxlong-3)/2)
+            i = max(0, (self.maxlong-3) // 2)
             j = max(0, self.maxlong-3-i)
             s = s[:i] + '...' + s[len(s)-j:]
         if s[-1] == 'L':
@@ -43,7 +50,7 @@ class BetterRepr(Repr, object):
         on it.  If it is an instance of list call self.repr_list() on it. Else
         call Repr.repr_instance().
         """
-        if isinstance(obj, exceptions.Exception):
+        if isinstance(obj, Exception):
             # Don't cut down exception strings so much.
             tms = self.maxstring
             self.maxstring = max(512, tms * 4)
@@ -91,7 +98,7 @@ class BetterRepr(Repr, object):
         if level <= 0: return '{...}'
         s = ''
         n = len(obj)
-        items = obj.items()[:min(n, self.maxdict)]
+        items = list(obj.items())[:min(n, self.maxdict)]
         items.sort()
         for key, val in items:
             entry = self.repr1(key, level-1) + ':' + self.repr1(val, level-1)