diff -r 000000000000 -r 6474c204b198 xpcom/tests/unit/test_systemInfo.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/tests/unit/test_systemInfo.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  const PROPERTIES = ["name", "host", "arch", "version", "pagesize",
+                      "pageshift", "memmapalign", "cpucount", "memsize"];
+  let sysInfo = Components.classes["@mozilla.org/system-info;1"].
+                getService(Components.interfaces.nsIPropertyBag2);
+
+  PROPERTIES.forEach(function(aPropertyName) {
+    print("Testing property: " + aPropertyName);
+    let value = sysInfo.getProperty(aPropertyName);
+    do_check_true(!!value);
+  });
+
+  // This property must exist, but its value might be zero.
+  print("Testing property: umask")
+  do_check_eq(typeof sysInfo.getProperty("umask"), "number");
+}