+ # Pretend to move *src* to *dst* with *plugin*. Some "what if"
+ # information will be output to stdout. This is useful to see if
+ # there would be (for example) a username collision at *dst* before
+ # attempting the move in earnest.
+ #
+ # @param cfg [Configuration] the configuration options to pass to
+ # the *plugin* we're runnning.
+ #
+ # @param plugin [Class] plugin class that will perform the move.
+ #
+ # @param src [User] the source user to be moved.
+ #
+ # @param dst [User] the destination user, to which we will move *src*.
+ #
+ def run(cfg, plugin, src, dst)