diff --git a/src/allmydata/test/test_web.py b/src/allmydata/test/test_web.py
index cd8b2e057..a7304c718 100644
--- a/src/allmydata/test/test_web.py
+++ b/src/allmydata/test/test_web.py
@@ -4,6 +4,7 @@ from StringIO import StringIO
 from twisted.application import service
 from twisted.trial import unittest
 from twisted.internet import defer, reactor
+from twisted.internet.task import Clock
 from twisted.web import client, error, http
 from twisted.python import failure, log
 from nevow import rend
@@ -119,7 +120,9 @@ class WebMixin(object):
         self.s = FakeClient()
         self.s.startService()
         self.staticdir = self.mktemp()
-        self.ws = webish.WebishServer(self.s, "0", staticdir=self.staticdir)
+        self.clock = Clock()
+        self.ws = webish.WebishServer(self.s, "0", staticdir=self.staticdir,
+                                      clock=self.clock)
         self.ws.setServiceParent(self.s)
         self.webish_port = port = self.ws.listener._port.getHost().port
         self.webish_url = "http://localhost:%d" % port
@@ -2873,7 +2876,8 @@ class Web(WebMixin, WebErrorMixin, testutil.StallMixin, unittest.TestCase):
             self.failUnless("finished" in data, res)
         d.addCallback(_check1)
         # the retain-for=0 will cause the handle to be expired very soon
-        d.addCallback(self.stall, 2.0)
+        d.addCallback(lambda ign:
+            self.clock.advance(2.0))
         d.addCallback(lambda ignored:
                       self.shouldHTTPError("test_ophandle_retainfor",
                                            404, "404 Not Found",
diff --git a/src/allmydata/web/operations.py b/src/allmydata/web/operations.py
index 7fbf8d270..8ee9f2027 100644
--- a/src/allmydata/web/operations.py
+++ b/src/allmydata/web/operations.py
@@ -24,10 +24,15 @@ class OphandleTable(rend.Page, service.Service):
     UNCOLLECTED_HANDLE_LIFETIME = 4*DAY
     COLLECTED_HANDLE_LIFETIME = 1*DAY
 
-    def __init__(self):
+    def __init__(self, clock=None):
         # both of these are indexed by ophandle
         self.handles = {} # tuple of (monitor, renderer, when_added)
         self.timers = {}
+        # The tests will provide a deterministic clock
+        # (twisted.internet.task.Clock) that they can control so that
+        # they can test ophandle expiration. If this is provided, I'll
+        # use it schedule the expiration of ophandles.
+        self.clock = clock
 
     def stopService(self):
         for t in self.timers.values():
@@ -103,7 +108,10 @@ class OphandleTable(rend.Page, service.Service):
     def _set_timer(self, ophandle, when):
         if ophandle in self.timers and self.timers[ophandle].active():
             self.timers[ophandle].cancel()
-        t = reactor.callLater(when, self._release_ophandle, ophandle)
+        if self.clock:
+            t = self.clock.callLater(when, self._release_ophandle, ophandle)
+        else:
+            t = reactor.callLater(when, self._release_ophandle, ophandle)
         self.timers[ophandle] = t
 
     def _release_ophandle(self, ophandle):
diff --git a/src/allmydata/web/root.py b/src/allmydata/web/root.py
index ee1cd9211..59ebfbdb5 100644
--- a/src/allmydata/web/root.py
+++ b/src/allmydata/web/root.py
@@ -145,10 +145,12 @@ class Root(rend.Page):
     addSlash = True
     docFactory = getxmlfile("welcome.xhtml")
 
-    def __init__(self, client):
+    def __init__(self, client, clock=None):
         rend.Page.__init__(self, client)
         self.client = client
-        self.child_operations = operations.OphandleTable()
+        # If set, clock is a twisted.internet.task.Clock that the tests
+        # use to test ophandle expiration.
+        self.child_operations = operations.OphandleTable(clock)
         try:
             s = client.getServiceNamed("storage")
         except KeyError:
diff --git a/src/allmydata/webish.py b/src/allmydata/webish.py
index 57b84ca58..8442bb25d 100644
--- a/src/allmydata/webish.py
+++ b/src/allmydata/webish.py
@@ -121,10 +121,15 @@ class MyRequest(appserver.NevowRequest):
 class WebishServer(service.MultiService):
     name = "webish"
 
-    def __init__(self, client, webport, nodeurl_path=None, staticdir=None):
+    def __init__(self, client, webport, nodeurl_path=None, staticdir=None,
+                                        clock=None):
         service.MultiService.__init__(self)
         # the 'data' argument to all render() methods default to the Client
-        self.root = root.Root(client)
+        # the 'clock' argument to root.Root is, if set, a
+        # twisted.internet.task.Clock that is provided by the unit tests
+        # so that they can test features that involve the passage of
+        # time in a deterministic manner.
+        self.root = root.Root(client, clock)
         self.buildServer(webport, nodeurl_path, staticdir)
         if self.root.child_operations:
             self.site.remember(self.root.child_operations, IOpHandleTable)