[Proj] How to validate a new projection?

[Michael Speth]

Greetings,
   As I've written to this list before, our team is working on 
implementing the HEALPix projection and developing a new projection for 
proj.4.

We have tested the forward and inverse projections against our python 
implementation and we believe the mathematical formulas are correct 
based on what has already been published for HEALPix; however, how can 
we determine that the outputs from the projection are correct?

Are there any standard procedures for validating new projections for 
proj.4?

Thank you for your help.

--
Michael Speth
Scientific Programmer
Landcare Research