src/third_party/mozjs-45/js/src/jit-test/tests/debug/Debugger-debuggees-02.js

// The array returned by getDebuggees is just a snapshot, not live.
var dbg = new Debugger;
var a1 = dbg.getDebuggees();
var g = newGlobal();
var gw = dbg.addDebuggee(g);
assertEq(gw instanceof Debugger.Object, true);
var a2 = dbg.getDebuggees();
assertEq(a2.length, 1);
assertEq(a2[0], gw);
assertEq(a1.length, 0);