Progressing the log range bug

[Ian Clatworthy]

Hi Marius,

It's great news that your changes are working for the MySQL folk. Let's
get the tests improved and get the change landed. For those following
along at home, here's the bug I'm taking about:
https://bugs.launchpad.net/bzr/+bug/484109.

Here's what I'd like you to do: add tests for the changes you've made
down at the branch.iter_merge_sorted_revisions() level. That's actually
the important tests in this case, rather than higher level log ones. If
branch.iter_merge_sorted_revisions() works, then log will work. :-)

The current tests can be found here:

  bzrlib/tests/per_branch/iter_merge_sorted_revisions.py

I hope the existing tests are well written and easy to copy-and-paste
from. Let me know if you run into problems. I'm around this week but
back on chemo next week (so around but brain dead then).

Ian C.