How to test raduis is working.. can't find radtest

[Luke Hammond]

I have just installed FreeRADIUS 2.07 i think it is.. anyways. i 
followed a tutorial on how to install in with MySQL on Centos 5 and when 
i get to the part about testing the database using radtest.. it doesnt 
work. radtest is not where it should be, have looked on google to try 
and work out where esactly this 'radtest' lives, but all the locations 
it i supposed to be.. it isnt!

So, where should it be and why isnt it there? do i have to install it 
separately?  Also, how do i test that my radius is working and accepting 
logins without it?