Does a test subdomain (site copy) affect SEO?

Question

Search Engine Optimization

There is a main site and a copy of this site, on a subdomain, to fix or add something there and throw it off on the battlefield. Can a test site on a subdomain be found in a search engine?

Answer 1

If it is not closed from indexing, sooner or later it will get into the index.

Answer 2

Additionally, write on each page in
You can also make a stub with a login password. The server response should be 401 Unauthorized