About debug means ---How to debug a function seperately in an easy way?

Hello, pgsql-hackers:

I want to debug one function in postgre backend.

for example, I want to debug the following function :

array_set(ArrayType *array,
int nSubscripts,
int *indx,
Datum dataValue,
bool isNull,
int arraytyplen,
int elmlen,
bool elmbyval,
char elmalign)

What I want is to set various inputs, and see the corresponding result.

Meanwhile , I don't know how to design the test case from the regular process, from TCOP, parser, analyzer,... and finally to array_set()

I just want to take it in an easy way, for example , I write some code somewhere in postgre backend source
code, and make up many different inputs and see the result returned by this function array_set.

Is there some convenient way to do it?

Thanks a lot ^_^

yours sincerely
　　　　　billywq(at)163(dot)com
　　　　　　　2008-12-15