[MERGE] add -c option to merge command (#141368)

[Ian Clatworthy]

Alexander Belchenko wrote:
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> 
> Actually adding -c option was quite trivial, but as usual test for changes
> is much bigger than actual changes.

Sweet.

bb:tweak


> +    def assertDirectoryContent(self, directory, entries, message=''):
> +        """Assert whether entries (files or directories) are exist
> +        in some directory. It's also check that there is no extra
> +        entries.
> +        """

As this is an internal method, I'd prefer a leading underscore on the
name. Some minor English grammar fixes needed as well. I suggest this ...

"""Assert whether entries (file or directories) exist in a directory.

It also checks that there are no extra entries.
"""

> +        ondisk = sorted(os.listdir(directory))
> +        if set(ondisk) == set(entries):
> +            return

As you're comparing sets, I think the sorted() bit is not required. If
you want to sort for the purposes of output, I'd sort after the return
and sort both ondisk and entries.

Ian C.