This is intended to test conformance between pygame and pygame_cffi

Status
======

Currently, it exercises parts the pygame.draw and pygame.transform modules

NOTE: On OSX (or possibly some other thing that's different), loading a file
      with transparent pixels returns slightly different RGB values for those
      pixels. Currently the `scale` test is affected by this.

Usage
=====

Run gen_conformance.py using pygame to create a set of test images
Run test_conformance.py using pygame_cffi to run the test and generate
a set of test and difference images for the cases which differ


Adding a test
=============

Write a function that takes a pygame surface as it's sole parameter and draws
the neccesary details on the surface. Import this in tests/__init__.py and add
a entry to the conformances_tests dictionary. The dictionary is keyed with the
test name.

Currently, the tests use 32-bit surfaces throughout.

Generated files
===============

results/gen_<test>.png - The generated conformance images
results/test_<test>.png - The corresponding test image
results/diff_<test>.png - The difference image. This is only created if the
                          images differ

