Your code looks valid to me : you are declaring two functions, called one and two ; and two is calling one.
Then, you can call any of those functions, to execute it.
For example, if you execute the following portion of code :
function one($test){
var_dump(__FUNCTION__);
return 1;
}
function two($id){
var_dump(__FUNCTION__);
one($id);
}
two('plop');
Note that I called two, in the last line of this example.
You'll get this kind of output :
string 'two' (length=3)
string 'one' (length=3)
Which shows that both functions were executed.
two(5)would not produce any output, so you cannot know whether it "worked" or not. In any case, have a look at: php.net/manual/en/language.functions.php