The code in this directory produces a test for Xdelta.  To run it you
have to edit the hard-coded constants at the top of the file, which
include "cmd_data_source", which should be the name of a big file
containing source data that the test uses to construct sample inputs.
This allows you to test on whatever kind of data you want, but the
synthetic edits are still hardcoded.  Have a look.

Of course, a better test would let you run it without any
configuration, but this is not that test.