Do I need to create a mirror for testing?

Question

Software testing

The client asked to create a mirror to test the site (only for the admin). Does it need to be done? Maybe there is another way to solve the problem. And how to implement it correctly so as not to copy everything.

Answer 1

So correct that the idea even got its own name in the development stages: staging.
dev (local copy of the developer, unstable) -> staging (test machine) -> production (production version)
It is to copy everything, that's the point - check it in conditions as close as possible to combat. Except perhaps the data, they can be fictitious.
Correctly done through the Continuous Integration server.

Answer 2

"Is it necessary or not" should be decided by the TOR or agreement with the client.
Again, what kind of testing:
- a constant sandbox running in parallel with the production site, to "play around with the functionality";
- a temporary sandbox to test the implementation of required functions, etc.
The first can be implemented inside the site in the form of a preview, if we are talking about a single element. Or about some kind of basket of changes, i.e. the admin changes the elements of the site, all changes are recorded and then they are changed on the site itself using a separate "apply" button (only the admin sees the change before the change is accepted).
For the second option, you can simply provide for resetting the settings to default and launching the same copy as production.