diff -r 000000000000 -r 6474c204b198 modules/libjar/test/unit/test_bug589292.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/libjar/test/unit/test_bug589292.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,22 @@
+// Make sure we behave appropriately when asking for content-disposition
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const path = "data/test_bug589292.zip";
+
+function run_test() {
+  var ios = Cc["@mozilla.org/network/io-service;1"].
+            getService(Ci.nsIIOService);
+  var spec = "jar:" + ios.newFileURI(do_get_file(path)).spec + "!/foo.txt";
+  var channel = ios.newChannel(spec, null, null);
+  instr = channel.open();
+  var val;
+  try {
+    val = channel.contentDisposition;
+    do_check_true(false, "The channel has content disposition?!");
+  } catch (e) {
+    // This is what we want to happen - there's no underlying channel, so no
+    // content-disposition header is available
+    do_check_true(true, "How are you reading this?!");
+  }
+}