// sufficient.
assertTrue(Object.isSealed(obj));
-assertDoesNotThrow(function() { obj.push(); });
-assertDoesNotThrow(function() { obj.unshift(); });
-assertDoesNotThrow(function() { obj.splice(0,0); });
+// Verify that the length can't be written by builtins.
+assertThrows(function() { obj.push(); }, TypeError);
+assertThrows(function() { obj.unshift(); }, TypeError);
+assertThrows(function() { obj.splice(0,0); }, TypeError);
assertTrue(Object.isFrozen(obj));
// Verify that an item can't be changed with splice.
assertThrows(function() { obj.splice(0,1,1); }, TypeError);
+assertTrue(Object.isFrozen(obj));
// Verify that unshift() with no arguments will fail if it reifies from
// the prototype into the object.