Since you did mention anything about your DB I am giving the suggestion based on both embedded and SQL DB.
lets first looks that prerequisites:
two host names, one for SEPM and one for SQL DB server (assuming you using one and are going to segregate it from production SEPM DB)
and two IP address as in above scenario
Now if you are using SEPM with embedded DB, simply clone the VM. Then change the IP address and host name of your TEST VM. finally you have you run management server configuration wizard to update the SEPM and DB hosts details in the DB and the MSL so that your test clients can communicate to test SEPM.
on the other hand if you are using an SQL DB the steps are similar with little changes where you will have to point the SEPM to your new test SQL server.