--- a/devtools/client/shared/shim/test/test_service_prefs.html
+++ b/devtools/client/shared/shim/test/test_service_prefs.html
@@ -138,21 +138,21 @@ function do_tests() {
   is(Services.prefs.getPrefType("devtools.branch1.somestring"),
     Services.prefs.PREF_STRING, "type of string pref");
 
   WrappedPrefs.setBoolPref("devtools.branch1.somebool", true);
   ok(WrappedPrefs.getBoolPref("devtools.branch1.somebool"), "set bool pref");
   WrappedPrefs.setIntPref("devtools.branch2.someint", -93);
   is(WrappedPrefs.getIntPref("devtools.branch2.someint"), -93, "set int pref");
   WrappedPrefs.setCharPref("devtools.branch1.somestring", "hello");
-  ok(WrappedPrefs.getCharPref("devtools.branch1.somestring"), "hello",
+  is(WrappedPrefs.getCharPref("devtools.branch1.somestring"), "hello",
     "set string pref");
 
   Services.prefs.clearUserPref("devtools.branch1.somestring");
-  ok(Services.prefs.getCharPref("devtools.branch1.somestring"), "dinosaurs",
+  is(Services.prefs.getCharPref("devtools.branch1.somestring"), "dinosaurs",
     "clear string pref");
 
   ok(Services.prefs.prefHasUserValue("devtools.branch1.somebool"),
     "bool pref has user value");
   ok(!Services.prefs.prefHasUserValue("devtools.branch1.somestring"),
     "string pref does not have user value");
 
 
@@ -162,19 +162,19 @@ function do_tests() {
 
   let branch0 = Services.prefs.getBranch(null);
   let branch1 = Services.prefs.getBranch("devtools.branch1.");
 
   branch1.setCharPref("somestring", "octopus");
   Services.prefs.setCharPref("devtools.branch1.somestring", "octopus");
   is(Services.prefs.getCharPref("devtools.branch1.somestring"), "octopus",
     "set correctly via branch");
-  ok(branch0.getCharPref("devtools.branch1.somestring"), "octopus",
+  is(branch0.getCharPref("devtools.branch1.somestring"), "octopus",
     "get via base branch");
-  ok(branch1.getCharPref("somestring"), "octopus", "get via branch");
+  is(branch1.getCharPref("somestring"), "octopus", "get via branch");
 
 
   let notifications = {};
   let clearNotificationList = () => { notifications = {}; }
   let observer = {
     observe: function (subject, topic, data) {
       notifications[data] = true;
     }