1 files changed, 38 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 000000000..7e1b0dcd7
--- /dev/null
+++ b/modules/libpref/test/unit_ipc/test_update_prefs.js
@@ -0,0 +1,38 @@
+var Ci = Components.interfaces;
+var Cc = Components.classes;
+
+function isParentProcess() {
+    let appInfo = Cc["@mozilla.org/xre/app-info;1"];
+    return (!appInfo || appInfo.getService(Ci.nsIXULRuntime).processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT);
+}
+
+function run_test() {
+  if (isParentProcess()) {
+
+    do_load_child_test_harness();
+
+    var pb = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+
+    // 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 = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+  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) {
+    do_check_eq(existsStr, "false");
+    do_test_finished();
+}
+\ No newline at end of file