Python version of unsigned integer 7-bit encoder and decoder

uint_7bit.py

#!/usr/bin/evn python
# -*- coding: utf8 -*-

def encode_to_7bit(value):
    """
    Encode unsigned int to 7-bit str data
    """
    data = []
    number = abs(value)
    while number >= 0x80:
        data.append((number | 0x80) & 0xff)
        number >>= 7
    data.append(number & 0xff)
    return ''.join(chr(char) for char in data)


def decode_from_7bit(data):
    """
    Decode 7-bit encoded int from str data
    """
    result = 0
    for index, char in enumerate(data):
        byte_value = ord(char)
        result |= (byte_value & 0x7f) << (7 * index)
        if byte_value & 0x80 == 0:
            break
    return result


def test():
    """
    Test encoding and decoding
    """

    value = 0
    res = encode_to_7bit(value)
    assert res == '\x00', 'Invalid encoding of %s' % value

    value = 127
    res = encode_to_7bit(value)
    assert res == '\x7f', 'Invalid encoding of %s' % value

    value = 256
    res = encode_to_7bit(value)
    assert res == '\x80\x02', 'Invalid encoding of %s' % value

    value = 0
    res = encode_to_7bit(value)
    assert decode_from_7bit(encode_to_7bit(value)) == value, 'Invalid decoding of %s' % value

    value = 42
    res = encode_to_7bit(value)
    assert decode_from_7bit(encode_to_7bit(value)) == value, 'Invalid decoding of %s' % value

    value = 1082376495
    res = encode_to_7bit(value)
    assert decode_from_7bit(encode_to_7bit(value)) == value, 'Invalid decoding of %s' % value
    

if __name__ == '__main__':
    try:
        test()
        print('OK')
    except Exception as ex:
        print('FAILED: %s' % ex)