string tolower and case insensitivity

[root@ve10:Active] config  b virtual bar list
virtual bar {
   snat automap
   destination 172.28.19.79:1812
   ip protocol 17
   rules myrule
   profiles {
      myudp {}
      radiusLB {}
   }
}
[root@ve10:Active] config  b profile myudp list
profile udp myudp {
   defaults from udp
   datagram lb enable
}
[root@ve10:Active] config  b pool test_pool1 list
pool test_pool1 {
   members 200.200.200.101:1812 {}
}
[root@ve10:Active] config  b pool test_pool2 list
pool test_pool2 {
   members 200.200.200.111:1812 {}
}
[root@ve10:Active] config  b rule myrule list
rule myrule {
   when CLIENT_DATA {
   log local0. "[RADIUS::avp User-Name]"
   if {[string tolower [RADIUS::avp User-Name]] ends_with "test.com"} {
      pool test_pool1
   } else {
      pool test_pool2
   }
}
when SERVER_CONNECTED {
   log local0. "[LB::server pool]"
   log local0. "[IP::remote_addr]:[UDP::remote_port]"
}
}

[root@ve10:Active] config  tail -f /var/log/ltm
Oct 11 11:17:20 local/tmm info tmm[7926]: Rule myrule : john@Test.com
Oct 11 11:17:20 local/tmm info tmm[7926]: Rule myrule : test_pool1
Oct 11 11:17:20 local/tmm info tmm[7926]: Rule myrule : 200.200.200.101:1812
Oct 11 11:17:27 local/tmm info tmm[7926]: Rule myrule : john@other.com
Oct 11 11:17:27 local/tmm info tmm[7926]: Rule myrule : test_pool2
Oct 11 11:17:27 local/tmm info tmm[7926]: Rule myrule : 200.200.200.111:1812