diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/surfaces-01.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/surfaces-01.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+// Check superficial characteristics of functions and properties (not functionality).
+
+function checkFunction(obj, name, nargs) {
+    var desc = Object.getOwnPropertyDescriptor(obj, name);
+    assertEq(desc.configurable, true, name + " should be configurable");
+    assertEq(desc.writable, true, name + " should be writable");
+    assertEq(desc.enumerable, false, name + " should be non-enumerable");
+    assertEq(desc.value, obj[name]);  // well obviously
+    assertEq(typeof desc.value, 'function', name + " should be a function");
+    assertEq(desc.value.length, nargs, name + " should have .length === " + nargs);
+}
+
+checkFunction(this, "Debugger", 1);
+
+assertEq(Debugger.prototype.constructor, Debugger);
+assertEq(Object.prototype.toString.call(Debugger.prototype), "[object Debugger]");
+assertEq(Object.getPrototypeOf(Debugger.prototype), Object.prototype);