def it_can_calculate_relative_ref_value(self):
cases = (
('/', '/ppt/presentation.xml', 'ppt/presentation.xml'),
('/ppt', '/ppt/slideMasters/slideMaster1.xml',
'slideMasters/slideMaster1.xml'),
('/ppt/slides', '/ppt/slideLayouts/slideLayout1.xml',
'../slideLayouts/slideLayout1.xml'),
)
for baseURI, uri_str, expected_relative_ref in cases:
pack_uri = PackURI(uri_str)
assert pack_uri.relative_ref(baseURI) == expected_relative_ref
