tests/test-mq-qsave.t

templater: define interface for objects requiring unwraphybrid()

Prepares for introducing another hybrid-like data type. show() takes context
as an argument so a wrapper class may render its items by pre-configured
template:

  def show(self, context, mapping):
      return (context.expand(self._tmpl, mapping + lm) for lm in self._mappings)

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init

  $ echo 'base' > base
  $ hg ci -Ambase
  adding base

  $ hg qnew -mmqbase mqbase

  $ hg qsave
  $ hg qrestore 2
  restoring status: hg patches saved state