michael@0: 
michael@0: function Foo(x)
michael@0: {
michael@0:   this.f = x + 10;
michael@0: }
michael@0: 
michael@0: var x = new Foo(0);
michael@0: assertEq(10, eval("x.f"));
michael@0: 
michael@0: called = false;
michael@0: Object.defineProperty(Foo.prototype, 'f', {set: function() { called = true; }});
michael@0: 
michael@0: var y = new Foo(0);
michael@0: assertEq(10, eval("x.f"));
michael@0: assertEq(undefined, eval("y.f"));
michael@0: assertEq(called, true);