library dependencies and unit/integration testing

[Ted Zlatanov]

This is in the context of package management (e.g. package.el/ELPA and
Emacsmirror).  I am not proposing anything, only trying to find out
what's currently possible.

What capabilities does Emacs offer for tracking library dependencies
beyond 'require and `load-history'?  I think versions (as stated by the
Version header) are not tracked and that's a basic requirement.  Then,
how would a library state it depends on "foo v.1 or later and bar v.2
exactly"?

In order to ensure these dependencies are tracked correctly, is there a
*standard* way in Emacs to test if a library loads and runs some basic
unit and integration tests correctly?

Ted