files above 2 levels can not be included using require_once or include

[ravi]

In PHP,

files above 2 levels can not be included using require, require_once or include or include_once directive.

For example, if file "test.php" is present as Docroot/level1/test.php.

There is another file below two or three levels as
DocRoot/levle1/level2/level3/filebelow.php

In the file "filebelow.php", I want to access "test.php" using require_once.
How can I do it ?

I tried with require_once("../../../test.php") without success.
I tried with require and iclude also without success.

Same is true if files to be included are below more than 2 levels.

Any answer ?

Thanks,
Ravi