automv: remove test for 'developer mode' The tests no longer use this mode, the test is entirely redundant.

automv: add some context for the tests

automv: simplify retrieving the status The default is to show the status in the current working copy, no need to pass in the parent and working copy context here.

tests: change branches test to work cross platform While it is not easy to make a file 000 on Windows, you can emulate most of the behaviors by replacing the file with a directory.

histedit: change string literals to constants in goal naming This is a part of bigger effort to refactor histedit with ultimate goal of understanding it.

run-tests: add --chg option to install and run tests using chg Because the temporary installation directory is shared between hg and chg, --chg is not allowed if --with-hg option is specified. Also, --chg option does not work on FreeBSD because "make" command is hard-coded. These limitations can be improved later. Almost all tests will fail with chg right now.

run-tests: add --with-chg option to run tests using chg Unlike --with-hg=/path/to/chg, this option allows us to start and clean up command servers in isolated environment. And we can specify the hg command as well as the chg command.

destutil: add more precise error classes for destmerge Having exception classes more precise than 'Abort' will allow us to properly catch "nothing to rebase" situations when we will be using 'destmerge' in rebase.

destutil: allow to disable the "on head check" in destmerge 'hg merge' refuses to pick a default destination if the working copy is not on a head. This is a very sensible default for 'hg merge' but 'hg rebase' should work in this situation. So we introduce a way to disable this check. It will soon be used by rebase.

destutil: allow to specify an explicit source for the merge We can now specify from where the merge is performed. The experimental revset is updated to take revisions as argument, allowing to test the feature. This will become very useful for pick the 'rebase' default destination. For this reason, we also exclude all descendants from the rebased set from the candidate destinations. This descendants exclusion was not necessary for merge as default destination would not be picked from anything else than a head. I'm not super excited with the current error messages, but I would prefer to delay an overall messages rework once 'hg rebase' is done getting a default destination aligned with 'hg merge'.