Make a copy of wordpress website on another domain

I was looking to make a copy of a wordpress site, at a new domain name. The reason for this is to test a new revamp at the new domain (basically for testing purposes). I have copied all files over to the new domain and installed wordpress. I know I need to change the ‘wp-options’ settings to change the wordpress database links, but I am wary that if I change these links, it will stop the original domain from working. The ‘wp-config’ settings have been changed, with a copy of the databse created on the new site.

To sum up, the orginal wordpress site ids to remain the same and untouched, but the new site, at a new domain, is to be a copy that we can make amends to for testing. Any help would be greatly appreciated.

Thanks.