from itertools import chain

import pytest
from datasets import load_dataset


def test_streaming_dataset():
    datasets = load_dataset("./cnn_dailymail_dutch.py", streaming=True)
    assert set(datasets.keys()) == {"train", "validation", "test"}

    for split in ["train", "validation", "test"]:
        ds = datasets[split]
        for i, e in enumerate(ds):
            assert 10 <= len(e["article"]) <= 11000
            assert 10 <= len(e["highlights"]) <= 500
            if i == 100:
                break


def test_train_split():
    ds = load_dataset("./cnn_dailymail_dutch.py", split="train" + f"[:{2000}]")
    assert len(ds) == 2000


def test_batch_dataset():
    datasets = load_dataset("./cnn_dailymail_dutch.py")
    assert set(datasets.keys()) == {"train", "validation", "test"}