test_cases = [
    {
        "predictions": [0, 0, 2],
        "result": {"mrr": 0.7777777777777778}
    },
    {
        "predictions": [0, 0],
        "result": {"mrr": 1}
    },
    {
        "predictions": [0, 4],
        "result": {"mrr": 0.6}
    }
]