Quick and dirty tests

I'm starting to test hash (sha256 and adler32)  and compression (gzip and lzma) algorithms. Right now the program breaks its executable file into pieces, and writes them compressed with gzip using their sha256 hash as a name.
Not much, but a beginning.
Now I'm thinking about how metadata should be stored, how to test for new files and modifications inside a file already backed up.
Next, I'll try to back a file up storing its metadata and restore it in other directory.
In order to detect changes in a file already backed up I need a rolling checksum algorithm. I've found an implementation and asked for permission for using it, giving proper credit, of course.