How to use NUnit to test native C++ code

//=========================================================================
// Calculates the CRC for a given buffer.
// 
// Example calculate the CRC for a GUID:
//	GUID g;
//	CoCreateGuid( &g );
//	crc = crc32( (unsigned char*)&g, sizeof( GUID ) );
// or
//	crc = crc16( (unsigned char*)&g, sizeof( GUID ) );
//
//=========================================================================


//=========================================================================
// CRC32 stuff.
//=========================================================================

//-------------------------------------------------------------------------
// Build auxiliary table for parallel byte-at-a-time CRC-32.
//-------------------------------------------------------------------------
#define CRC32_POLY 0x04c11db7     // AUTODIN II, Ethernet, & FDDI

inline long* getCrc32Table()
{
	static long crc32Table[256];
	return crc32Table;
}

//-------------------------------------------------------------------------
// Initialized first time "crc32()" is called. If you prefer, you can
// statically initialize it at compile time. [Another exercise.]
//-------------------------------------------------------------------------

inline void InitCRC32()
{
      	int i, j;
        unsigned long c;

        for (i = 0; i < 256; ++i)
	{
               	for (c = i << 24, j = 8; j > 0; --j)
                       	c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1);

                getCrc32Table()[i] = c;
       	}
}


inline unsigned long crc32( unsigned char *buf, int len)
{
        unsigned char *p;
        unsigned long  crc;

	// if not already done, build table
        if (!getCrc32Table()[1])    
                InitCRC32();

	// preload shift register, per CRC-32 spec
        crc = 0xffffffff;       

        for ( p = buf; len > 0; ++p, --len )
                crc = ( crc << 8 ) ^ getCrc32Table()[( crc >> 24 ) ^ *p];

	// transmit complement, per CRC-32 spec
        return ~crc;            

}


//=========================================================================
// CRC16 stuff.
//=========================================================================


inline unsigned short* getCrc16Table()
{
    static unsigned short crc16Table[256];
    return crc16Table;
}

inline void InitCRC16(void)
{
      int i, j;
      unsigned short k;

      for (i = 0; i < 256; i++)
      {
            k = 0xC0C1;
            for (j = 1; j < 256; j <<= 1)
            {
                  if (i & j)
                        getCrc16Table()[i] ^= k;
                  k = (unsigned short)( (k << (short)1) ^ 0x4003 );
            }
      }
}


inline unsigned short crc16( unsigned char *buf, unsigned nbytes )
{
      unsigned char     *p;
      unsigned char     *lim;
      unsigned short    crc = 0;

      // if not already done, build table
      if (!getCrc16Table()[1])    
          InitCRC16();

      p = buf;
      lim = p + nbytes;

      while (p < lim)
            crc = (unsigned short) ( (crc >> (short)8 ) ^ getCrc16Table()[(crc & 0xFF) ^ *p++] );

      return crc;
}