dirstate-v2: backup the data file during the transaction (
issue6730)
If we backup of the docket, without doing a backup of the data file, we
highly risk restoring a docket pointing to a missing file in the future.
So we now backup the data-file alongside the docket.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.