Test context handling
---------------------

    >>> import gmpy2
    >>> from gmpy2 import mpfr,mpc,get_context,set_context,ieee,context,local_context

Test ieee()
-----------

    >>> ieee(32)
    context(precision=24, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=128, emin=-148,
            subnormalize=True,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> ieee(64)
    context(precision=53, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1024, emin=-1073,
            subnormalize=True,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> ieee(128)
    context(precision=113, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=16384, emin=-16493,
            subnormalize=True,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> set_context(ieee(32))
    >>> gmpy2.const_pi().digits(2)
    ('110010010000111111011011', 2, 24)
    >>> set_context(ieee(64))
    >>> gmpy2.const_pi().digits(2)
    ('11001001000011111101101010100010001000010110100011000', 2, 53)
    >>> set_context(ieee(128))
    >>> gmpy2.const_pi().digits(2)
    ('11001001000011111101101010100010001000010110100011000010001101001100010011000110011000101000101110000000110111000', 2, 113)

Test context()
--------------

    >>> context()
    context(precision=53, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> context(precision=100)
    context(precision=100, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> context(real_prec=100)
    context(precision=53, real_prec=100, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> context(real_prec=100,imag_prec=200)
    context(precision=53, real_prec=100, imag_prec=200,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)

Test get_context()
------------------

    >>> set_context(context())
    >>> get_context()
    context(precision=53, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> a=get_context()
    >>> a.precision=100
    >>> a
    context(precision=100, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> get_context()
    context(precision=100, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> b=a.copy()
    >>> b.precision=200
    >>> b
    context(precision=200, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> a
    context(precision=100, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)
    >>> get_context()
    context(precision=100, real_prec=Default, imag_prec=Default,
            round=RoundToNearest, real_round=Default, imag_round=Default,
            emax=1073741823, emin=-1073741823,
            subnormalize=False,
            trap_underflow=False, underflow=False,
            trap_overflow=False, overflow=False,
            trap_inexact=False, inexact=False,
            trap_invalid=False, invalid=False,
            trap_erange=False, erange=False,
            trap_divzero=False, divzero=False,
            trap_expbound=False,
            allow_complex=False)

Test local_context()
--------------------

>>> set_context(context())
>>> with local_context() as ctx:
...   print(ctx.precision)
...   ctx.precision+=20
...   print(ctx.precision)
...
53
73
>>> get_context()
context(precision=53, real_prec=Default, imag_prec=Default,
        round=RoundToNearest, real_round=Default, imag_round=Default,
        emax=1073741823, emin=-1073741823,
        subnormalize=False,
        trap_underflow=False, underflow=False,
        trap_overflow=False, overflow=False,
        trap_inexact=False, inexact=False,
        trap_invalid=False, invalid=False,
        trap_erange=False, erange=False,
        trap_divzero=False, divzero=False,
        trap_expbound=False,
        allow_complex=False)
>>> with local_context(ieee(64)) as ctx:
...   print(ctx)
...
context(precision=53, real_prec=Default, imag_prec=Default,
        round=RoundToNearest, real_round=Default, imag_round=Default,
        emax=1024, emin=-1073,
        subnormalize=True,
        trap_underflow=False, underflow=False,
        trap_overflow=False, overflow=False,
        trap_inexact=False, inexact=False,
        trap_invalid=False, invalid=False,
        trap_erange=False, erange=False,
        trap_divzero=False, divzero=False,
        trap_expbound=False,
        allow_complex=False)
>>> get_context()
context(precision=53, real_prec=Default, imag_prec=Default,
        round=RoundToNearest, real_round=Default, imag_round=Default,
        emax=1073741823, emin=-1073741823,
        subnormalize=False,
        trap_underflow=False, underflow=False,
        trap_overflow=False, overflow=False,
        trap_inexact=False, inexact=False,
        trap_invalid=False, invalid=False,
        trap_erange=False, erange=False,
        trap_divzero=False, divzero=False,
        trap_expbound=False,
        allow_complex=False)
>>> with get_context() as ctx:
...   print(ctx.precision)
...   ctx.precision+=100
...   print(ctx.precision)
...
53
153
>>> get_context()
context(precision=53, real_prec=Default, imag_prec=Default,
        round=RoundToNearest, real_round=Default, imag_round=Default,
        emax=1073741823, emin=-1073741823,
        subnormalize=False,
        trap_underflow=False, underflow=False,
        trap_overflow=False, overflow=False,
        trap_inexact=False, inexact=False,
        trap_invalid=False, invalid=False,
        trap_erange=False, erange=False,
        trap_divzero=False, divzero=False,
        trap_expbound=False,
        allow_complex=False)
>>> with local_context(precision=200) as ctx:
...   print(ctx.precision)
...   ctx.precision+=100
...   print(ctx.precision)
...
200
300
>>> get_context()
context(precision=53, real_prec=Default, imag_prec=Default,
        round=RoundToNearest, real_round=Default, imag_round=Default,
        emax=1073741823, emin=-1073741823,
        subnormalize=False,
        trap_underflow=False, underflow=False,
        trap_overflow=False, overflow=False,
        trap_inexact=False, inexact=False,
        trap_invalid=False, invalid=False,
        trap_erange=False, erange=False,
        trap_divzero=False, divzero=False,
        trap_expbound=False,
        allow_complex=False)