michael@0: load(libdir + "asserts.js");
michael@0: 
michael@0: /*
michael@0:  * Throw a TypeError if the trap defines a non-configurable property that does
michael@0:  * not exist on the target
michael@0:  */
michael@0: assertThrowsInstanceOf(function () {
michael@0:     Object.defineProperty(new Proxy({}, {
michael@0:         defineProperty: function (target, name, desc) {
michael@0:             return true;
michael@0:         }
michael@0:     }), 'foo', {
michael@0:         configurable: false
michael@0:     });
michael@0: }, TypeError);