diff -r 000000000000 -r 6474c204b198 netwerk/test/unit/test_bug660066.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netwerk/test/unit/test_bug660066.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,42 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+Components.utils.import("resource://gre/modules/NetUtil.jsm");
+const SIMPLEURI_SPEC = "data:text/plain,hello world";
+const BLOBURI_SPEC = "blob:123456";
+
+function do_info(text, stack) {
+  if (!stack)
+    stack = Components.stack.caller;
+
+  dump( "\n" +
+       "TEST-INFO | " + stack.filename + " | [" + stack.name + " : " +
+       stack.lineNumber + "] " + text + "\n");
+}
+
+function do_check_uri_neq(uri1, uri2)
+{
+  do_info("Checking equality in forward direction...");
+  do_check_false(uri1.equals(uri2));
+  do_check_false(uri1.equalsExceptRef(uri2));
+
+  do_info("Checking equality in reverse direction...");
+  do_check_false(uri2.equals(uri1));
+  do_check_false(uri2.equalsExceptRef(uri1));
+}
+
+function run_test()
+{
+  var simpleURI = NetUtil.newURI(SIMPLEURI_SPEC);
+  var fileDataURI = NetUtil.newURI(BLOBURI_SPEC);
+
+  do_info("Checking that " + SIMPLEURI_SPEC + " != " + BLOBURI_SPEC);
+  do_check_uri_neq(simpleURI, fileDataURI);
+
+  do_info("Changing the nsSimpleURI spec to match the nsFileDataURI");
+  simpleURI.spec = BLOBURI_SPEC;
+
+  do_info("Verifying that .spec matches");
+  do_check_eq(simpleURI.spec, fileDataURI.spec);
+
+  do_info("Checking that nsSimpleURI != nsFileDataURI despite their .spec matching")
+  do_check_uri_neq(simpleURI, fileDataURI);
+}