diff -r 000000000000 -r 6474c204b198 toolkit/devtools/server/tests/unit/test_getyoungestframe.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/devtools/server/tests/unit/test_getyoungestframe.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,30 @@
+function run_test()
+{
+  Components.utils.import("resource://gre/modules/jsdebugger.jsm");
+  addDebuggerToGlobal(this);
+  var xpcInspector = Cc["@mozilla.org/jsinspector;1"].getService(Ci.nsIJSInspector);
+  var g = testGlobal("test1");
+
+  var dbg = new Debugger();
+  dbg.uncaughtExceptionHook = testExceptionHook;
+
+  dbg.addDebuggee(g);
+  dbg.onDebuggerStatement = function(aFrame) {
+    do_check_true(aFrame === dbg.getNewestFrame());
+    // Execute from the nested event loop, dbg.getNewestFrame() won't
+    // be working anymore.
+
+    do_execute_soon(function() {
+      try {
+        do_check_true(aFrame === dbg.getNewestFrame());
+      } finally {
+        xpcInspector.exitNestedEventLoop("test");
+      }
+    });
+    xpcInspector.enterNestedEventLoop("test");
+  };
+
+  g.eval("function debuggerStatement() { debugger; }; debuggerStatement();");
+
+  dbg.enabled = false;
+}