The Tor Browser / file revision

 // Map.prototype.get and .has basically work

 var m = new Map;

 function rope() {

     var s = "s";

     for (var i = 0; i < 16; i++)

         s += s;

     return s;

 }

 var keys = [undefined, null, true, false,

             0, 1, 65535, 65536, 2147483647, 2147483648, 4294967295, 4294967296,

             -1, -65536, -2147483648,

             0.5, Math.sqrt(81), Math.PI,

             Number.MAX_VALUE, -Number.MAX_VALUE, Number.MIN_VALUE, -Number.MIN_VALUE,

             NaN, Infinity, -Infinity,

             "", "\0", "a", "ab", "abcdefg", rope(),

             {}, [], /a*b/, Object.prototype, Object];

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

     // without being set

     var key = keys[i];

     assertEq(m.has(key), false);

     assertEq(m.get(key), undefined);

     // after being set

     var v = {};

     assertEq(m.set(key, v), undefined);

     assertEq(m.has(key), true);

     assertEq(m.get(key), v);

     // after being deleted

     assertEq(m.delete(key), true);

     assertEq(m.has(key), false);

     assertEq(m.get(key), undefined);

     m.set(key, v);

 }

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

     assertEq(m.has(keys[i]), true);