Thanks Jongware for your help, when i try
Test[a].parent.locked = true;
All work good here 
But now, some TextFrame in my document have Tag XML, so they are not empty.
When the sript is run, the file is in the final part of execution, we no longer need XML Tag.
So i want ( on the TextFrame only ) cancel tag before test if the TextFrame is empty.
I'm absolutely not familiar with XML & Indesign, can you give mea helping hand for solve it ?