diff --git a/mozilla/xpcom/tests/TestID.cpp b/mozilla/xpcom/tests/TestID.cpp
index e69de29bb2d..5b73101920c 100644
--- a/mozilla/xpcom/tests/TestID.cpp
+++ b/mozilla/xpcom/tests/TestID.cpp
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "NPL"); you may not use this file except in
+ * compliance with the NPL.  You may obtain a copy of the NPL at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the NPL is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
+ * for the specific language governing rights and limitations under the
+ * NPL.
+ *
+ * The Initial Developer of this code under the NPL is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
+ * Reserved.
+ */
+#include <stdio.h>
+#include "plstr.h"
+#include "nsID.h"
+
+static char* ids[] = {
+  "5C347B10-D55C-11D1-89B7-006008911B81",
+  "{5C347B10-D55C-11D1-89B7-006008911B81}",
+  "5c347b10-d55c-11d1-89b7-006008911b81",
+  "{5c347b10-d55c-11d1-89b7-006008911b81}",
+
+  "FC347B10-D55C-F1D1-F9B7-006008911B81",
+  "{FC347B10-D55C-F1D1-F9B7-006008911B81}",
+  "fc347b10-d55c-f1d1-f9b7-006008911b81",
+  "{fc347b10-d55c-f1d1-f9b7-006008911b81}",
+};
+#define NUM_IDS (sizeof(ids) / sizeof(ids[0]))
+
+int main(int argc, char** argv)
+{
+  nsID id;
+  for (int i = 0; i < NUM_IDS; i++) {
+    char* idstr = ids[i];
+    if (!id.Parse(idstr)) {
+      fprintf(stderr, "TestID: Parse failed on test #%d\n", i);
+      return -1;
+    }
+    char* cp = id.ToString();
+    if (NULL == cp) {
+      fprintf(stderr, "TestID: ToString failed on test #%d\n", i);
+      return -1;
+    }
+    if (0 != PL_strcmp(cp, ids[4*(i/4) + 3])) {
+      fprintf(stderr, "TestID: compare of ToString failed on test #%d\n", i);
+      return -1;
+    }
+  }
+
+  return 0;
+}