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 // Test that the watch handler is not called recursively for the same object

 // and property.

 (function() {

     var obj1 = {}, obj2 = {};

     var handler_entry_count = 0;

     var handler_exit_count = 0;

     obj1.watch('x', handler);

     obj1.watch('y', handler);

     obj2.watch('x', handler);

     obj1.x = 1;

     assertEq(handler_entry_count, 3);

     assertEq(handler_exit_count, 3);

     function handler(id) {

         handler_entry_count++;

         assertEq(handler_exit_count, 0);

         switch (true) {

           case this === obj1 && id === "x":

             assertEq(handler_entry_count, 1);

             obj2.x = 3;

             assertEq(handler_exit_count, 2);

             break;

           case this === obj2 && id === "x":

             assertEq(handler_entry_count, 2);

             obj1.y = 4;

             assertEq(handler_exit_count, 1);

             break;

           default:

             assertEq(this, obj1);

             assertEq(id, "y");

             assertEq(handler_entry_count, 3);

             // We expect no more watch handler invocations

             obj1.x = 5;

             obj1.y = 6;

             obj2.x = 7;

             assertEq(handler_exit_count, 0);

             break;

         }

         ++handler_exit_count;

         assertEq(handler_entry_count, 3);

     }

 })();

 // Test that run-away recursion in watch handlers is properly handled.  

 (function() {

     var obj = {};

     var i = 0;

     try {

         handler();

         throw new Error("Unreachable");

     } catch(e) {

         assertEq(e instanceof InternalError, true);

     }

     function handler() {

         var prop = "a" + ++i;

         obj.watch(prop, handler);

         obj[prop] = 2;

     }

 })();