diff -r 000000000000 -r 6474c204b198 netwerk/test/unit/test_gre_resources.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netwerk/test/unit/test_gre_resources.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,27 @@
+// test that things that are expected to be in gre-resources are still there
+
+var ios = Cc["@mozilla.org/network/io-service;1"]. getService(Ci.nsIIOService);
+
+function wrapInputStream(input)
+{
+  var nsIScriptableInputStream = Components.interfaces.nsIScriptableInputStream;
+  var factory = Components.classes["@mozilla.org/scriptableinputstream;1"];
+  var wrapper = factory.createInstance(nsIScriptableInputStream);
+  wrapper.init(input);
+  return wrapper;
+}
+
+function check_file(file) {
+  var channel = ios.newChannel("resource://gre-resources/"+file, null, null);
+  try {
+    let instr = wrapInputStream(channel.open());
+    do_check_true(instr.read(1024).length > 0)
+  } catch (e) {
+    do_throw("Failed to read " + file + " from gre-resources:"+e)
+  }
+}
+
+function run_test() {
+  for each(let file in ["charsetData.properties"])
+    check_file(file)
+}