Sorting Tuples

Hi to all.

INTRODUCTION:
I created a patch for PostgreSQL even if i'm not a PostgreSQL user. I
just wanted to implement an idea for possibly getting better External
Sorting module on PostgreSQL just using some basic C programming
knowledge and now I'm facing to using PostgreSQL for a while in order to
test my patch.
My patch "activates" when user is trying to sort a load of data more or
less twice bigger than his available memory (e.g.: sorting 5GB of data
just disposing of 1GB of available memory)

PROBLEM:
First of all I want to realise my patch does sorts correctly or not. But
it's a little bit difficult to check when

    SELECT * FROM huge_table ORDER BY a_column_of_huge_table;

means checking a 4 or 5 GB result...

QUESTION:
Is there a way to discover if data is sorted correctly other than
spending 2 months taking a look to the 5 GB result tuples, one by one?

Thanks for your attention.
Regards, Manolo.