Make tests run on all platforms ('-script.py' suffix on windows)

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branch : tests-win
extra : amend_source : 6294e9ff16dab3468171082596239909b2b2cea4
Added support for 'project = .'

--HG--
branch : project-at-root
extra : amend_source : c1200ab33ef6c63ab5c190e4fc9b706bbe6a518f
Merge changes from tests-win

--HG--
branch : project-at-root