Assuming you have new enough code, this should work for you:
event manager applet shut-TEST
event none
action 1.0 cli command "enable"
action 2.0 cli command "show int descr | inc TEST"
action 3.0 cli command "config t"
action 4.0 foreach line $_cli_result "\n"
action 4.1 regexp "^([A-Za-z0-9\.\:/]+).*TEST" $line match intf
action 4.2 if $_regexp_result eq 1
action 4.3 cli command "int $intf"
action 4.4 cli command "shut"
action 4.5 end
action 5.0 end
action 6.0 cli command "end"
