Looks like currently an error is raised when long is too small:
```
In [3]: int8(a)
---------------------------------------------------------------------------
OverflowError                             Traceback (most recent call last)
/home/charris/<ipython-input-3-74f0ef5792f6> in <module>()
----> 1 int8(a)

OverflowError: Python int too large to convert to C long
```
These cases need to be part of the tests, including tests for the exceptions raised for certain values. Unfortunately, the size of long depends on the OS. For 64 bit Windows it is 32 bits, for 64 bit Linux it is 64 bits, so the tests will need to be OS dependent. Hmm, I think one of the include files has the number of bits in long.