michael@0: load(libdir + "asserts.js");
michael@0: 
michael@0: var target = {};
michael@0: Object.getOwnPropertyDescriptor(new Proxy(target, {
michael@0:   getOwnPropertyDescriptor: function () {
michael@0:     return {value: 2, configurable: true};
michael@0:    }
michael@0: }), 'foo');
michael@0: 
michael@0: var target = {};
michael@0: Object.preventExtensions(target);
michael@0: assertThrowsInstanceOf(function () {
michael@0:   Object.getOwnPropertyDescriptor(new Proxy(target, {
michael@0:     getOwnPropertyDescriptor: function () {
michael@0:         return {value: 2, configurable: true};
michael@0:     }
michael@0:   }), 'foo');
michael@0: }, TypeError);