The Tor Browser / file revision

 var desc = Object.getOwnPropertyDescriptor(Debugger.prototype, "enabled");

 assertEq(typeof desc.get, 'function');

 assertEq(typeof desc.set, 'function');

 var g = newGlobal();

 var hits;

 var dbg = new Debugger(g);

 assertEq(dbg.enabled, true);

 dbg.onDebuggerStatement = function () { hits++; };

 var vals = [true, false, null, undefined, NaN, "blah", {}];

 for (var i = 0; i < vals.length; i++) {

     dbg.enabled = vals[i];

     assertEq(dbg.enabled, !!vals[i]);

     hits = 0;

     g.eval("debugger;");

     assertEq(hits, vals[i] ? 1 : 0);

 }