diff -r 000000000000 -r 6474c204b198 netwerk/test/unit/test_force_sniffing.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netwerk/test/unit/test_force_sniffing.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,90 @@
+// This file tests the flag LOAD_TREAT_APPLICATION_OCTET_STREAM_AS_UNKNOWN.
+
+Cu.import("resource://testing-common/httpd.js");
+
+const octetStreamType = "application/octet-stream";
+const sniffedType = "application/x-sniffed";
+
+const snifferCID = Components.ID("{954f3fdd-d717-4c02-9464-7c2da617d21d}");
+const snifferContract = "@mozilla.org/network/unittest/contentsniffer;1";
+const categoryName = "content-sniffing-services";
+
+var sniffer = {
+  QueryInterface: function sniffer_qi(iid) {
+    if (iid.equals(Components.interfaces.nsISupports) ||
+        iid.equals(Components.interfaces.nsIFactory) ||
+        iid.equals(Components.interfaces.nsIContentSniffer))
+      return this;
+    throw Components.results.NS_ERROR_NO_INTERFACE;
+  },
+  createInstance: function sniffer_ci(outer, iid) {
+    if (outer)
+      throw Components.results.NS_ERROR_NO_AGGREGATION;
+    return this.QueryInterface(iid);
+  },
+  lockFactory: function sniffer_lockf(lock) {
+    throw Components.results.NS_ERROR_NOT_IMPLEMENTED;
+  },
+  getMIMETypeFromContent: function (request, data, length) {
+    return sniffedType;
+  }
+};
+
+var listener = {
+  onStartRequest: function test_onStartR(request, ctx) {
+    // We should have sniffed the type of the file.
+    var chan = request.QueryInterface(Components.interfaces.nsIChannel);
+    do_check_eq(chan.contentType, sniffedType);
+  },
+
+  onDataAvailable: function test_ODA() {
+    throw Components.results.NS_ERROR_UNEXPECTED;
+  },
+
+  onStopRequest: function test_onStopR(request, ctx, status) {
+    do_test_finished();
+  }
+};
+
+function handler(metadata, response) {
+  response.setHeader("Content-Type", octetStreamType);
+}
+
+function makeChan(url) {
+  var ios = Components.classes["@mozilla.org/network/io-service;1"]
+                      .getService(Components.interfaces.nsIIOService);
+  var chan = ios.newChannel(url, null, null);
+  // Force sniffing if we have "application/octet-stream" as Content-Type
+  chan.loadFlags |= Components.interfaces
+                              .nsIChannel
+                              .LOAD_TREAT_APPLICATION_OCTET_STREAM_AS_UNKNOWN;
+
+  return chan;
+}
+
+XPCOMUtils.defineLazyGetter(this, "url", function() {
+  return "http://localhost:" + httpserv.identity.primaryPort + "/test";
+});
+
+var httpserv = null;
+
+function run_test() {
+  httpserv = new HttpServer();
+  httpserv.registerPathHandler("/test", handler);
+  httpserv.start(-1);
+
+  // Register our fake sniffer that always returns the content-type we want.
+  Components.manager.nsIComponentRegistrar.registerFactory(snifferCID,
+                       "Unit test content sniffer", snifferContract, sniffer);
+
+  var catMan = Components.classes["@mozilla.org/categorymanager;1"]
+                         .getService(Components.interfaces.nsICategoryManager);
+  catMan.nsICategoryManager.addCategoryEntry(categoryName, snifferContract,
+                                             snifferContract, false, true);
+
+  var chan = makeChan(url);
+  chan.asyncOpen(listener, null);
+
+  do_test_pending();
+}
+