def test_wagner_beethoven(): wagner_beethoven = list(operas_both_at_premiere("wagner", "beethoven")) assert len(wagner_beethoven) == 0
def test_beethoven_mozart(): beethoven_mozart = list(operas_both_at_premiere("beethoven", "mozart")) assert len(beethoven_mozart) == 5 assert "Apollo and Hyacinth" not in beethoven_mozart
def test_beethoven_wagner(): beethoven_wagner = list(operas_both_at_premiere("beethoven", "wagner")) assert len(beethoven_wagner) == 0