The testing environment needed depends on the type pf 
application you test as well as the process that exists 
within the organisation. However on a broad level, there 
will be test environments, which is for the internal 
testing team, The UAT environment which is for the cllient 
acceptance test area and finally the production environment.

The testing environment whether the internal test or the 
UAT environement should be same or tends to the same 
environement both in rescpect to hardware and software 
environemt should be same so that same tupes of bugs, 
defects, failure or anything such may be created and that 
should be resolved.

The testing environment whether the internal test or the 
UAT environement should be same or tends to the same 
environement both in rescpect to hardware and software 
environemt should be same so that same tupes of bugs, 
defects, failure or anything such may be created and that 
should be resolved.

I am not sure I understand your question. If your question 
if your question is How should be the test environment look 
like then it should be a replica of production by all means 
which is mostly handled by a hardward engineer. And incase 
your question is related to how many test environments are 
required? The usual test environment, UAT and generally 
another instance to test the ot fixes if need to be deplyed 
to production or check the concerns from production (This 
would be an exact replica of prod from time to time.)