saint19 :
Hi and welcome to Tom's forum.
Yes, you can do it in that way and will work without problems.
With a very expensive tester yes you can do it this way.
With a normal tester (one not costing $5k + ) no it wont work that way.
You need to remove the wire from the swtich and test them individually that way.
Doing it the way you asked about will resullt in bad test results and likely a fired tester or switch.