Testing of gmpy2 pack and unpack
--------------------------------

    >>> import gmpy2 as G
    >>> from gmpy2 import mpz,pack,unpack

Test
----

    >>> x = mpz(0)
    >>> all((x == pack(unpack(x,i),i) for i in range(1,100)))
    True
    >>> x = mpz(1)
    >>> all((x == pack(unpack(x,i),i) for i in range(1,100)))
    True
    >>> x = mpz(2)
    >>> all((x == pack(unpack(x,i),i) for i in range(1,100)))
    True
    >>> x = mpz(3141592635)
    >>> all((x == pack(unpack(x,i),i) for i in range(1,100)))
    True
    >>> x = mpz(1234567891234567890000000000000000000000000000000000000123)
    >>> all((x == pack(unpack(x,i),i) for i in range(1,100)))
    True
    >>> x = mpz(1) << 500
    >>> all((x == pack(unpack(x,i),i) for i in range(1,200)))
    True
    >>> x -= 1
    >>> all((x == pack(unpack(x,i),i) for i in range(1,200)))
    True