1 files changed, 34 insertions, 0 deletions
diff --git a/modules/libpref/test/unit_ipc/test_update_prefs.js b/modules/libpref/test/unit_ipc/test_update_prefs.js
new file mode 100644
index 0000000000..51e2c458c5
--- /dev/null
+++ b/modules/libpref/test/unit_ipc/test_update_prefs.js
@@ -0,0 +1,34 @@
+function isParentProcess() {
+  return Services.appinfo.processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
+}
+
+function run_test() {
+  if (isParentProcess()) {
+    do_load_child_test_harness();
+
+    var pb = Services.prefs;
+
+    // these prefs are set after the child has been created.
+    pb.setBoolPref("Test.IPC.bool.new", true);
+    pb.setIntPref("Test.IPC.int.new", 23);
+    pb.setCharPref("Test.IPC.char.new", "hey");
+
+    run_test_in_child("test_observed_prefs.js", testPrefClear);
+  }
+}
+
+function testPrefClear() {
+  var pb = Services.prefs;
+  pb.clearUserPref("Test.IPC.bool.new");
+
+  sendCommand(
+    'var pb = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);\n' +
+      'pb.prefHasUserValue("Test.IPC.bool.new");\n',
+    checkWasCleared
+  );
+}
+
+function checkWasCleared(existsStr) {
+  Assert.equal(existsStr, "false");
+  do_test_finished();
+}