def test_display_books_plus(python_books, limit, expected, capfd):
display_books(python_books, limit=limit)
output = capfd.readouterr()[0].splitlines()
assert len(output) == expected
def test_display_books(python_books, index, expected, capfd):
display_books(python_books, year=2017)
output = capfd.readouterr()[0].splitlines()
assert output[index] == expected