Cleanup RefUpdateTest

Application code, including unit tests for storage implementations,
should not extend RevCommit outside of the scope of using it for a
RevWalk.  Its a lot of overhead and unlikely to work long-term.

Instead for the one test that matters, use a custom subclass of the
ObjectId type.  This lets us measure exactly what we are looking for,
which is that the subclass isn't retained.

A lot of other tests were unnecessarily wrapping an object with a
RevCommit and storing that back into the RefUpdate.  This is just
retesting what the earlier no-cache test was doing, and complicated
the test considerably.  Drop that code and just rely on the value that
was configured by the helper method.

Change-Id: I5b31813484eaa306e9bc4de9622dd5bd4846b16d
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
1 file changed