`shuffle` function test case

[hwwhww]

Generated this one very simple test in Python side. Before the standardized testing format, can dear other clients sides help to check in your codebase as well? :)

import pytest

from beacon_chain.state.helpers import (
    shuffle,
)

@pytest.mark.parametrize(
    (
        'values,seed,expect'
    ),
    [
        (
            [i for i in range(100)],
            b"\x8d\x8dd\xb9\x84\x05*Bw\xf5\x87\xdd\x04nj\xee\x82\xfc9\xb9\x19\x82'x!#p];\xa5\x8e\xc9",
            [87, 32, 76, 41, 61, 9, 44, 78, 70, 42, 8, 6, 79, 37, 4, 67, 3, 66, 55, 0, 69, 98, 38, 47, 20, 31, 48, 97, 34, 33, 96, 63, 91, 15, 1, 77, 39, 64, 58, 53, 82, 49, 26, 29, 5, 65, 19, 86, 74, 23, 46, 14, 10, 51, 85, 89, 57, 73, 71, 52, 88, 30, 16, 81, 24, 22, 36, 45, 12, 2, 62, 93, 18, 72, 83, 95, 13, 21, 27, 28, 80, 43, 68, 59, 94, 60, 99, 56, 92, 54, 25, 75, 7, 90, 50, 35, 11, 84, 17, 40],
        ),
        (
            [i for i in range(12)],
            b"&P\x18'\x91\xf6\x8f\xc8;<\xb8\x8f\x1d\x92?\xad4\xb5\xb8\x0b\xca\x8a'\x8e\xae'\xcf7\xa3(\xb2\x8d",
            [7, 3, 2, 5, 11, 9, 1, 0, 4, 6, 10, 8],

        )
    ],
)
def test_shuffle_consistent(values, seed, expect):
    assert shuffle(values, seed) == expect

Updated: added Lighthouse's testcase.

[hwwhww]

cc @@paulhauner I just tested lighthouse's testcase, works for Python side too! 👍

[hwwhww]

Ahh sorry! Just updated the testcase again. Thank you @mkalinin! :)