--- a/toolkit/components/places/tests/cpp/test_IHistory.cpp
+++ b/toolkit/components/places/tests/cpp/test_IHistory.cpp
@@ -34,16 +34,18 @@
  * and other provisions required by the GPL or the LGPL. If you do not delete
  * the provisions above, a recipient may use your version of this file under
  * the terms of any one of the MPL, the GPL or the LGPL.
  *
  * ***** END LICENSE BLOCK ***** */
 
 #include "places_test_harness.h"
 #include "nsIBrowserHistory.h"
+#include "nsIPrefService.h"
+#include "nsIPrefBranch.h"
 
 #include "mock_Link.h"
 using namespace mozilla::dom;
 
 /**
  * This file tests the IHistory interface.
  */
 
@@ -122,16 +124,32 @@ private:
 NS_IMPL_ISUPPORTS1(
   VisitURIObserver,
   nsIObserver
 )
 
 ////////////////////////////////////////////////////////////////////////////////
 //// Test Functions
 
+void
+test_set_places_enabled()
+{
+  // Ensure places is enabled for everyone.
+  nsresult rv;
+  nsCOMPtr<nsIPrefBranch> prefBranch =
+    do_GetService(NS_PREFSERVICE_CONTRACTID, &rv);
+  do_check_success(rv);
+
+  rv = prefBranch->SetBoolPref("places.history.enabled", PR_TRUE);
+  do_check_success(rv);
+
+  // Run the next test.
+  run_next_test();
+}
+
 // These variables are shared between part 1 and part 2 of the test.  Part 2
 // sets the nsCOMPtr's to nsnull, freeing the reference.
 namespace test_unvisited_does_not_notify {
   nsCOMPtr<nsIURI> testURI;
   nsCOMPtr<Link> testLink;
 }
 void
 test_unvisted_does_not_notify_part1()
@@ -580,16 +598,17 @@ test_two_null_links_same_uri()
 
 ////////////////////////////////////////////////////////////////////////////////
 //// Test Harness
 
 /**
  * Note: for tests marked "Order Important!", please see the test for details.
  */
 Test gTests[] = {
+  TEST(test_set_places_enabled), // Must come first!
   TEST(test_unvisted_does_not_notify_part1), // Order Important!
   TEST(test_visited_notifies),
   TEST(test_unvisted_does_not_notify_part2), // Order Important!
   TEST(test_same_uri_notifies_both),
   TEST(test_unregistered_visited_does_not_notify), // Order Important!
   TEST(test_new_visit_notifies_waiting_Link),
   TEST(test_RegisterVisitedCallback_returns_before_notifying),
   TEST(test_observer_topic_dispatched),