diff -r 000000000000 -r 6474c204b198 docshell/test/browser/browser_bug388121-1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/docshell/test/browser/browser_bug388121-1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,26 @@
+function test() {
+  waitForExplicitFinish(); 
+
+  var newTab;
+  var newBrowser;
+  const secMan = Cc["@mozilla.org/scriptsecuritymanager;1"].getService(Ci.nsIScriptSecurityManager);
+
+  function testLoad(event) {
+    newBrowser.removeEventListener("load", testLoad, true);
+    is (event.target, newBrowser.contentDocument, "Unexpected target");
+    var prin = newBrowser.contentDocument.nodePrincipal;
+    isnot(prin, null, "Loaded principal must not be null");
+    isnot(prin, undefined, "Loaded principal must not be undefined");
+    is(secMan.isSystemPrincipal(prin), false,
+       "Loaded principal must not be system");
+    gBrowser.removeTab(newTab);
+
+    finish();
+  }
+
+  newTab = gBrowser.addTab();
+  newBrowser = gBrowser.getBrowserForTab(newTab);
+  newBrowser.contentWindow.location.href = "about:blank"
+  newBrowser.addEventListener("load", testLoad, true);
+}
+