import pytest
from unwind.imdb import imdb_rating_from_score, score_from_imdb_rating


@pytest.mark.parametrize("rating", (x / 10 for x in range(10, 101)))
def test_rating_conversion(rating):
    assert rating == imdb_rating_from_score(score_from_imdb_rating(rating))


@pytest.mark.parametrize("score", range(0, 101))
def test_score_conversion(score):
    # Because our score covers 101 discrete values and IMDb's rating only 91
    # discrete values, the mapping is non-injective, i.e. 10 values can't be
    # mapped uniquely.
    non_injective = set(range(5, 100, 10))
    if score in non_injective:
        pytest.skip(f"Score cannot be mapped back correctly: {score}")

    assert score == score_from_imdb_rating(imdb_rating_from_score(score))