Testing for SQL Errors in ISQL

I Would like to test on ISQL by passing invalid DBName or username or Password and grep for Strings like "Login Failed" or "Permission Denied" Etc. How to achieve this??

Tried this already:

${isql} -S {WRONGDBNAME} -U {USERNAME} -P{PASSWORD} >${tmp_file} <EO_ISQL>

if grep "Login Failed" ${tmp_file} echo "login failed" exit 0 else echo "login passed" exit 1 fi

Getting message "login passed" as output here.