sampy3/tests/test_bitstream.py

from typing import List, Union, Type, Optional
import pytest
from sampy.raknet.bitstream import Bitstream, get_bit_length


@pytest.mark.parametrize("value", [
    b"",
    b"A",
    b"AB",
    b"\xFF\x00\xAA\x55",
])
def test_from_bytes(value: bytes):
    bitstream = Bitstream.from_bytes(value)
    assert len(bitstream) == (len(value) << 3)
    assert bytes(bitstream) == value


@pytest.mark.parametrize("value,length,expected", [
    (0b0, 0, None),
    (0b1, 1, None),
    (0b0, 1, None),
    (0b1011, 4, None),
    (0b10111011, 8, None),
    (0b10111011, 7, 0b0111011),  # -> 0b0111011
])
def test_from_int(value: int, length: int, expected: int):
    bitstream = Bitstream.from_int(value, length)
    assert len(bitstream) == length
    assert len(bytes(bitstream)) == ((length + 7) >> 3)
    assert bitstream.bits == [bool(value & (1 << i)) for i in range(length-1, -1, -1)]
    if expected is not None:
        expected_bitstream = Bitstream.from_int(expected, length)
        assert bitstream.bits == expected_bitstream.bits
        assert bytes(bitstream) == bytes(expected_bitstream)


@pytest.mark.parametrize("values", [
    [True, False, False, True, True],
    [[True], [False, True], [False, False]],
    [b"a", b"bc"],
    [b"aa", b"b"],
    [Bitstream.from_bytes(b"A"), Bitstream.from_int(0b1011, 4), Bitstream.from_bytes(b"B")],
    [True, b"A", b"B", [False, True], Bitstream.from_int(0b10110, 5), False],
])
def test_init(values: List[Union[bool, List[bool], bytes, Bitstream]]):
    bitstream = Bitstream(*values)

    bitstream.seek(0)
    for item in values:
        bit_length = get_bit_length(item)
        if type(item) is bool:
            item = [item]

        read_type = bool if type(item) is list else type(item)
        value = bitstream.read(read_type, bit_length)
        assert value == item


def test_getitem():
    sample_values = [True, False, False, True, False, True, True, True, True, False]

    for length in range(1, len(sample_values)):
        values = sample_values[:length]
        bitstream = Bitstream(values)
        for i in range(length):
            assert bitstream[i] == values[i]
            assert bitstream[-i - 1] == values[-i - 1]  # For inverse lookup


def test_getitem_index_error():
    bitstream = Bitstream(True)
    with pytest.raises(IndexError):
        bitstream[1]
    with pytest.raises(IndexError):
        bitstream[-2]  # Inverse IndexError


@pytest.mark.parametrize("value", [
    True,
    [True, True],
    b"A",
    Bitstream(True, b"C"),
])
def test_setitem(value: Union[bool, List[bool], bytes, Bitstream]):
    bit_length = get_bit_length(value)
    read_type = bool if type(value) is list else type(value)
    for length in range(10):
        for i in range(length - bit_length + 1):
            bitstream = Bitstream([False] * length)
            bitstream[i] = value
            assert bitstream.read(read_type, bit_length, i) == (value if type(value) is not bool else [value])
            assert len(bitstream) == length


@pytest.mark.parametrize("value,equals,not_equals", [
    (
        [],
        [[]],
        [[True], [False]]
    ),
    (
        True,
        [[True]],
        [[False], [True, False], b"A"]
    ),
    (
        [True, False],
        [[True, False]],
        [[False], [False, False], b"A"]
    ),
    (
        b"A",
        [b"A", b"A", Bitstream.from_bytes(b"A"), Bitstream.from_bytes(b"A").bits],
        [[], [False], b"B", b"B", Bitstream.from_bytes(b"B"), Bitstream.from_bytes(b"B").bits]
    ),
    (
        b"ABC",
        [b"ABC"],
        [[], [False], b"A"]
    ),
])
def test_eq(
        value: Union[bool, List[bool], bytes, Bitstream],
        equals: List[Union[bool, List[bool], bytes, Bitstream]],
        not_equals: List[Union[bool, List[bool], bytes, Bitstream]]):
    bitstream = Bitstream(value)
    for equal in equals:
        assert bitstream == equal
    for not_equal in not_equals:
        assert bitstream != not_equal


@pytest.mark.parametrize("values,number,expected", [
    ([], 2, []),
    ([True, False], 2, [True, False, True, False]),
    (b"A", 2, b"AA"),
    ([False], 3, [False, False, False]),
])
def test_mul(
        values: Union[bool, List[bool], bytes, Bitstream],
        number: int,
        expected: Union[List[bool], bytes, Bitstream]):
    bitstream = Bitstream(values)

    assert (bitstream * number) == expected
    assert bitstream == values

    bitstream *= number
    assert bitstream == expected


@pytest.mark.parametrize("init_values,add_value,expected", [
    ([], True, [True]),
    ([True, False], False, [True, False, False]),
    (b"A", b"B", b"AB"),
])
def test_add(
        init_values: Union[bool, List[bool], bytes, Bitstream],
        add_value: Union[bool, List[bool], bytes, Bitstream],
        expected: Union[List[bool], bytes, Bitstream]):
    bitstream = Bitstream(init_values)

    assert (bitstream + add_value) == expected
    assert len(bitstream) == get_bit_length(init_values)

    bitstream += add_value
    assert bitstream == expected


@pytest.mark.parametrize("init_values", [
    [],
    [True, False],
    [b"A"],
    [True, b"B"],
])
def test_iter(init_values: List[Union[bool, List[bool], bytes, Bitstream]]):
    bitstream = Bitstream(*init_values)
    assert len(list(bitstream)) == len(bitstream)
    for index, bit in enumerate(bitstream):
        assert bit == bitstream[index]


@pytest.mark.parametrize("init_values,expected", [
    ([], b""),
    ([b"A"], b"A"),
    ([False], b"\x00"),
    ([[False] * 6, True], b"\x02"),
    ([[False] * 7, True], b"\x01"),
])
def test_bytes(
        init_values: List[Union[bool, List[bool], bytes, Bitstream]],
        expected: bytes):
    assert bytes(Bitstream(*init_values)) == expected


@pytest.mark.parametrize("init_values,expected", [
    ([], []),
    ([b"\x01"], [False] * 7 + [True]),
    ([False], [False]),
    ([False] * 6 + [True], [False] * 6 + [True]),
    ([False] * 7 + [True], [False] * 7 + [True]),
])
def test_bits(
        init_values: List[Union[bool, List[bool], bytes, Bitstream]],
        expected: List[bool]):
    assert Bitstream(*init_values).bits == expected


def test_copy():
    bitstream = Bitstream(True, False)
    bitstream_copy = bitstream.copy()
    assert bitstream == bitstream_copy
    assert id(bitstream) != id(bitstream.copy)


@pytest.mark.parametrize("lst", [
    [False] * 10,
    [True] * 10,
    [True, False] * 5,
    [False, True] * 5,
])
def test_append(lst: List[bool]):
    bitstream = Bitstream()
    for i in range(len(lst)):
        bitstream.append(lst[i])
        assert bitstream[i] == lst[i]
        assert len(bitstream) == (i + 1)


@pytest.mark.parametrize("extend_value", [
    [True, False, True],
    b"A",
    b"BB",
    Bitstream(True, b"C"),
])
def test_extend(extend_value: Union[List[bool], bytes, Bitstream]):
    for i in range(10):
        bitstream = Bitstream([False] * i)
        bitstream.extend(extend_value)
        value = bitstream.read(bool if type(extend_value) is list else type(extend_value), get_bit_length(extend_value), i)
        assert value == extend_value


def test_extend_error():
    bitstream = Bitstream()
    with pytest.raises(TypeError):
        bitstream.extend(True)


def test_clear():
    bitstream = Bitstream(b"A", [True, False, False, True])
    bitstream._offset = 3
    bitstream.clear()
    assert len(bitstream) == 0
    assert len(bytes(bitstream)) == 0
    assert bitstream._offset == 0


@pytest.mark.parametrize("lst", [
    [False] * 10,
    [True] * 10,
    [True, False] * 5,
    [False, True] * 5,
])
def test_pop(lst: List[bool]):
    bitstream = Bitstream(lst)
    for i in range(len(bitstream)):
        assert bitstream.pop() == lst[-i - 1]

    with pytest.raises(IndexError):
        assert bitstream.pop()


def test_read():
    bitstream = Bitstream(True, b"A", False, True, False)

    assert bitstream.read(bool, 1) == [True]
    assert bitstream.read(bytes, 8) == b"A"
    assert bitstream.read(int, 3) == 2

    bitstream.seek(0)
    assert bitstream.read(Bitstream, len(bitstream) - 1) == Bitstream(True, b"A", False, True)


@pytest.mark.parametrize("bitstream,read_type,bit_length,bit_index,expected", [
    (
        Bitstream(True, b"A", False, True, False),
        bool, 1, 0,
        [True]
    ),
    (
        Bitstream(True, b"A", False, True, False),
        bool, 3, 8 + 1,
        [False, True, False]
    ),
    (
        Bitstream(True, b"A", False, True, False),
        bytes, 8, 1,
        b"A"
    ),
    (
        Bitstream(True, b"A", False, True, False),
        Bitstream, 1 + 8 + 3, 0,
        Bitstream(True, b"A", False, True, False)
    ),
    (
        Bitstream(True, b"A", False, True, False),
        int, 3, 1 + 8,
        2
    ),
])
def test_read_index(
        bitstream: Bitstream,
        read_type: Type[Union[bool, bytes, Bitstream, int]],
        bit_length: int,
        bit_index: Optional[int],
        expected: Union[List[bool], bytes, Bitstream, int]):
    value = bitstream.read(read_type, bit_length, bit_index)

    if read_type is bool:
        assert type(value) == list
    else:
        assert type(value) == read_type
    assert value == expected


def test_read_error():
    bitstream = Bitstream(True, b"A", False, True, False)

    with pytest.raises(IndexError):
        bitstream.read(bool, 1, len(bitstream))

    with pytest.raises(IndexError):
        bitstream.read(bool, 1, -1)

    with pytest.raises(TypeError):
        bitstream.read(list, 1, 0)


@pytest.mark.parametrize("bitstream,value,bit_index,current_offset", [
    (Bitstream(), True, None, None),
    (Bitstream(), b"A", None, None),
    (Bitstream(), True, 0, None),
    (Bitstream(), True, 3, None),
    (Bitstream(), True, 7, None),
    (Bitstream(), True, 8, None),
    (Bitstream(False), True, None, None),
    (Bitstream(False), True, 0, None),
    (Bitstream(False), True, 0, 0),
    (Bitstream(False), True, None, 0),
])
def test_write(bitstream: Bitstream, value: Union[bool, List[bool], bytes, Bitstream], bit_index: Optional[int], current_offset: Optional[int]):
    if current_offset is not None:
        bitstream.seek(current_offset)

    bit_length = get_bit_length(value)
    bitstream.write(value, bit_index)

    if bit_index is None:
        bitstream.seek(-bit_length, 1)
        read_value = bitstream.read(bool if type(value) is list else type(value), bit_length)
    else:
        read_value = bitstream.read(bool if type(value) is list else type(value), bit_length, bit_index)

    assert read_value == ([value] if type(value) is bool else value)


def test_seek():
    bitstream = Bitstream([True] * 8)

    bitstream.seek(4, 0)
    assert bitstream._offset == 4

    bitstream.seek(-1, 1)
    assert bitstream._offset == 3

    bitstream.seek(-1, 2)
    assert bitstream._offset == 7