diff --git a/tests/util/test_logcontext.py b/tests/util/test_logcontext.py

index ad78d884e0..c54001f7a4 100644
--- a/tests/util/test_logcontext.py
+++ b/tests/util/test_logcontext.py
@@ -1,12 +1,11 @@
 import twisted.python.failure
-from twisted.internet import defer
-from twisted.internet import reactor
-from .. import unittest
+from twisted.internet import defer, reactor
 
-from synapse.util.async import sleep
-from synapse.util import logcontext
+from synapse.util import Clock, logcontext
 from synapse.util.logcontext import LoggingContext
 
+from .. import unittest
+
 
 class LoggingContextTestCase(unittest.TestCase):
 
@@ -22,18 +21,20 @@ class LoggingContextTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_sleep(self):
+        clock = Clock(reactor)
+
         @defer.inlineCallbacks
         def competing_callback():
             with LoggingContext() as competing_context:
                 competing_context.request = "competing"
-                yield sleep(0)
+                yield clock.sleep(0)
                 self._check_test_key("competing")
 
         reactor.callLater(0, competing_callback)
 
         with LoggingContext() as context_one:
             context_one.request = "one"
-            yield sleep(0)
+            yield clock.sleep(0)
             self._check_test_key("one")
 
     def _test_run_in_background(self, function):
@@ -87,7 +88,7 @@ class LoggingContextTestCase(unittest.TestCase):
     def test_run_in_background_with_blocking_fn(self):
         @defer.inlineCallbacks
         def blocking_function():
-            yield sleep(0)
+            yield Clock(reactor).sleep(0)
 
         return self._test_run_in_background(blocking_function)