michael@0: let ioService = Cc["@mozilla.org/network/io-service;1"]
michael@0:                 .getService(Ci.nsIIOService);
michael@0: let resProt = ioService.getProtocolHandler("resource")
michael@0:               .QueryInterface(Ci.nsIResProtocolHandler);
michael@0: 
michael@0: function run_test() {
michael@0:     // Define a resource:// alias that points to another resource:// URI.
michael@0:     let greModulesURI = ioService.newURI("resource://gre/modules/", null, null);
michael@0:     resProt.setSubstitution("my-gre-modules", greModulesURI);
michael@0: 
michael@0:     // When we ask for the alias, we should not get the resource://
michael@0:     // URI that we registered it for but the original file URI.
michael@0:     let greFileSpec = ioService.newURI("modules/", null,
michael@0:                                        resProt.getSubstitution("gre")).spec;
michael@0:     let aliasURI = resProt.getSubstitution("my-gre-modules");
michael@0:     do_check_eq(aliasURI.spec, greFileSpec);
michael@0: 
michael@0:     // Resolving URIs using the original resource path and the alias
michael@0:     // should yield the same result.
michael@0:     let greNetUtilURI = ioService.newURI("resource://gre/modules/NetUtil.jsm",
michael@0:                                          null, null);
michael@0:     let myNetUtilURI = ioService.newURI("resource://my-gre-modules/NetUtil.jsm",
michael@0:                                         null, null);
michael@0:     do_check_eq(resProt.resolveURI(greNetUtilURI),
michael@0:                 resProt.resolveURI(myNetUtilURI));
michael@0: }