diff --git a/src/allmydata/test/test_deferredutil.py b/src/allmydata/test/test_deferredutil.py
new file mode 100644
index 000000000..fcff77b54
--- /dev/null
+++ b/src/allmydata/test/test_deferredutil.py
@@ -0,0 +1,76 @@
+"""
+Tests for allmydata.util.deferredutil.
+
+Ported to Python 3.
+"""
+
+from __future__ import unicode_literals
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from future.utils import PY2
+if PY2:
+    from builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, int, list, object, range, str, max, min  # noqa: F401
+
+from twisted.trial import unittest
+from twisted.internet import defer, reactor
+from twisted.python.failure import Failure
+
+from allmydata.util import deferredutil
+
+
+class DeferredUtilTests(unittest.TestCase, deferredutil.WaitForDelayedCallsMixin):
+    def test_gather_results(self):
+        d1 = defer.Deferred()
+        d2 = defer.Deferred()
+        res = deferredutil.gatherResults([d1, d2])
+        d1.errback(ValueError("BAD"))
+        def _callb(res):
+            self.fail("Should have errbacked, not resulted in %s" % (res,))
+        def _errb(thef):
+            thef.trap(ValueError)
+        res.addCallbacks(_callb, _errb)
+        return res
+
+    def test_success(self):
+        d1, d2 = defer.Deferred(), defer.Deferred()
+        good = []
+        bad = []
+        dlss = deferredutil.DeferredListShouldSucceed([d1,d2])
+        dlss.addCallbacks(good.append, bad.append)
+        d1.callback(1)
+        d2.callback(2)
+        self.failUnlessEqual(good, [[1,2]])
+        self.failUnlessEqual(bad, [])
+
+    def test_failure(self):
+        d1, d2 = defer.Deferred(), defer.Deferred()
+        good = []
+        bad = []
+        dlss = deferredutil.DeferredListShouldSucceed([d1,d2])
+        dlss.addCallbacks(good.append, bad.append)
+        d1.addErrback(lambda _ignore: None)
+        d2.addErrback(lambda _ignore: None)
+        d1.callback(1)
+        d2.errback(ValueError())
+        self.failUnlessEqual(good, [])
+        self.failUnlessEqual(len(bad), 1)
+        f = bad[0]
+        self.failUnless(isinstance(f, Failure))
+        self.failUnless(f.check(ValueError))
+
+    def test_wait_for_delayed_calls(self):
+        """
+        This tests that 'wait_for_delayed_calls' does in fact wait for a
+        delayed call that is active when the test returns. If it didn't,
+        Trial would report an unclean reactor error for this test.
+        """
+        def _trigger():
+            #print "trigger"
+            pass
+        reactor.callLater(0.1, _trigger)
+
+        d = defer.succeed(None)
+        d.addBoth(self.wait_for_delayed_calls)
+        return d
diff --git a/src/allmydata/test/test_util.py b/src/allmydata/test/test_util.py
index 65ba308d9..b6f2074aa 100644
--- a/src/allmydata/test/test_util.py
+++ b/src/allmydata/test/test_util.py
@@ -15,7 +15,7 @@ from twisted.python.failure import Failure
 from twisted.python import log
 
 from allmydata.util import base32, idlib, mathutil, hashutil
-from allmydata.util import assertutil, fileutil, deferredutil, abbreviate
+from allmydata.util import assertutil, fileutil, abbreviate
 from allmydata.util import limiter, time_format, pollmixin
 from allmydata.util import statistics, dictutil, pipeline, yamlutil
 from allmydata.util import log as tahoe_log
@@ -750,60 +750,6 @@ class PollMixinTests(unittest.TestCase):
         d.addCallbacks(_suc, _err)
         return d
 
-class DeferredUtilTests(unittest.TestCase, deferredutil.WaitForDelayedCallsMixin):
-    def test_gather_results(self):
-        d1 = defer.Deferred()
-        d2 = defer.Deferred()
-        res = deferredutil.gatherResults([d1, d2])
-        d1.errback(ValueError("BAD"))
-        def _callb(res):
-            self.fail("Should have errbacked, not resulted in %s" % (res,))
-        def _errb(thef):
-            thef.trap(ValueError)
-        res.addCallbacks(_callb, _errb)
-        return res
-
-    def test_success(self):
-        d1, d2 = defer.Deferred(), defer.Deferred()
-        good = []
-        bad = []
-        dlss = deferredutil.DeferredListShouldSucceed([d1,d2])
-        dlss.addCallbacks(good.append, bad.append)
-        d1.callback(1)
-        d2.callback(2)
-        self.failUnlessEqual(good, [[1,2]])
-        self.failUnlessEqual(bad, [])
-
-    def test_failure(self):
-        d1, d2 = defer.Deferred(), defer.Deferred()
-        good = []
-        bad = []
-        dlss = deferredutil.DeferredListShouldSucceed([d1,d2])
-        dlss.addCallbacks(good.append, bad.append)
-        d1.addErrback(lambda _ignore: None)
-        d2.addErrback(lambda _ignore: None)
-        d1.callback(1)
-        d2.errback(ValueError())
-        self.failUnlessEqual(good, [])
-        self.failUnlessEqual(len(bad), 1)
-        f = bad[0]
-        self.failUnless(isinstance(f, Failure))
-        self.failUnless(f.check(ValueError))
-
-    def test_wait_for_delayed_calls(self):
-        """
-        This tests that 'wait_for_delayed_calls' does in fact wait for a
-        delayed call that is active when the test returns. If it didn't,
-        Trial would report an unclean reactor error for this test.
-        """
-        def _trigger():
-            #print "trigger"
-            pass
-        reactor.callLater(0.1, _trigger)
-
-        d = defer.succeed(None)
-        d.addBoth(self.wait_for_delayed_calls)
-        return d
 
 class HashUtilTests(unittest.TestCase):
 
diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index fd679e014..3196a8f90 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -21,6 +21,7 @@ PORTED_MODULES = [
 ]
 
 PORTED_TEST_MODULES = [
+    "allmydata.test.test_deferredutil",
     "allmydata.test.test_humanreadable",
     "allmydata.test.test_python3",
 ]