I am running a WordPress based site on example.com with its original content.
I then have another site running on example.me which is basically the exact copy of the original example.com together with all example.com's content and I'm using this example.me only for testing purposes, to develop and test new plugins and functionality which I then deploy on the main domain example.com.
I use the default WordPress settings on example.me that disables robots from crawling the site, but WordPress warns that this may not always work.
Is there any other way to let Google know straight away that this site example.me is a duplicate of example.com and is not be indexed?
Some kind of general canonical tag that I could use for the entire site?
Is there maybe a setting in webmaster tools to have this done?