diff --git a/src/allmydata/check_results.py b/src/allmydata/check_results.py
index 068f77a25..f33c3afc0 100644
--- a/src/allmydata/check_results.py
+++ b/src/allmydata/check_results.py
@@ -1,3 +1,4 @@
+from past.builtins import unicode
 
 from zope.interface import implementer
 from allmydata.interfaces import ICheckResults, ICheckAndRepairResults, \
@@ -56,7 +57,11 @@ class CheckResults(object):
         self._list_incompatible_shares = list_incompatible_shares
         self._count_incompatible_shares = count_incompatible_shares
 
-        assert isinstance(summary, str) # should be a single string
+        # On Python 2, we can mix bytes and Unicode. On Python 3, we want
+        # unicode.
+        if isinstance(summary, bytes):
+            summary = unicode(summary, "utf-8")
+        assert isinstance(summary, unicode)  # should be a single string
         self._summary = summary
         assert not isinstance(report, str) # should be list of strings
         self._report = report
diff --git a/src/allmydata/test/test_checker.py b/src/allmydata/test/test_checker.py
index 0d5877abe..e8f7e3ce1 100644
--- a/src/allmydata/test/test_checker.py
+++ b/src/allmydata/test/test_checker.py
@@ -1,5 +1,16 @@
+"""
+Ported to Python 3.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 from future.utils import PY2
-from past.builtins import unicode
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
+
 
 import json
 import os.path, shutil
@@ -161,7 +172,7 @@ class WebResultsRendering(unittest.TestCase):
                     "service-name": "storage",
                     "anonymous-storage-FURL": furl,
                     "permutation-seed-base32": "",
-                    "nickname": unicode(nickname),
+                    "nickname": str(nickname),
                     "app-versions": {}, # need #466 and v2 introducer
                     "my-version": "ver",
                     "oldest-supported": "oldest",
@@ -671,7 +682,7 @@ class BalancingAct(GridTestMixin, unittest.TestCase):
             "This little printing function is only meant for < 26 servers"
         shares_chart = {}
         names = dict(zip([ss.my_nodeid
-                          for _,ss in self.g.servers_by_number.iteritems()],
+                          for _,ss in self.g.servers_by_number.items()],
                          letters))
         for shnum, serverid, _ in self.find_uri_shares(uri):
             shares_chart.setdefault(shnum, []).append(names[serverid])
diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index 7ca18da15..f88f4f489 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -89,6 +89,7 @@ PORTED_TEST_MODULES = [
     "allmydata.test.test_abbreviate",
     "allmydata.test.test_base32",
     "allmydata.test.test_base62",
+    "allmydata.test.test_checker",
     "allmydata.test.test_codec",
     "allmydata.test.test_common_util",
     "allmydata.test.test_configutil",