def test_publication_year_is_not_converted_if_missing(self):
book = Book()
book.publication_year = None
csl = ReferenceToCSL.convert(book)
self.assertEqual(csl['issued'], {'raw': None})
def test_publication_year_is_converted(self):
book = Book()
book.publication_year = 2009
csl = ReferenceToCSL.convert(book)
self.assertEqual(csl['issued'], {'raw': '2009'})
