int vs long

[Gribouillis]

Here is what I got in a python 2 console

Python 2.7.12 (default, Dec  4 2017, 14:50:18) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.maxint
9223372036854775807
>>> sys.maxint + 1
9223372036854775808L
>>> sys.maxint + 1 == 2 ** 63
True
>>> - sys.maxint - 1
-9223372036854775808
>>> - sys.maxint - 2
-9223372036854775809L

So a good test seems to be

>>> def int_suffices(n):
...     return - 2 ** 63 <= n < 2 ** 63
...
# OR
>>> def int_suffices(n): return n >> 63 in (-1, 0)
...