michael@0: function foo(a, b) {
michael@0:     var s = "foo";
michael@0:     for (var j = 0; j < 5; j++)
michael@0:         s += a[b[j]];
michael@0:     return s;
michael@0: }
michael@0: 
michael@0: var a = {a:"zero", b:"one", c:"two", d:"three", e:"four"};
michael@0: var b = ["a", "b", "c", "d", "e"];
michael@0: 
michael@0: for (var i=0; i<9; i++)
michael@0:     assertEq(foo(a, b), "foozeroonetwothreefour");
michael@0: 
michael@0: a.e = 4;
michael@0: assertEq(foo(a, b), "foozeroonetwothree4");