From http://code.google.com/p/unittestpp/issues/detail?id=7

Some of the tests in TestMemoryOutStream.cpp are assuming that ULONG_MAX is exactly equal to
4294967295 (0xFFFFFFFF).

This turns out not to be true on Mac OS X compiled for -arch x86_64, where sizeof(long) = 8 and
therefore ULONG_MAX is 18446744073709551615 (0xFFFFFFFFFFFFFFFF).

The simple fix is to replace this file's use of ULONG_MAX with 0xFFFFFFFFUL.