GSoC project status: PgCheck - Integrity check for data files

Hello,
I am working on the GSoC project : PgCheck - Integrity check for data files.
Unfortunately, this project is still in its beginning, because my
examination period was during the June.  Right now I am working on
function, which will check the validity of indexes according to the
indexed table. This test should be one of various tests that should
check the integrity of data stored in database.
As other things that should be tested in order to check the validity of
data I see:
-check whether the constrains applied on items are fulfilled
-in case of variable-length data, compare the formal and actual size of
data
-check integrity of data pages
-etc.
I would be happy to hear any comments or recommendation on what should
be checked in order to validation of data integrity.
I have opened project on PgFoundry called: PgCheck-Integrity check for
data files. (just waiting for acceptance).
I will keep updating the status of my project.

Cheers,

Robert