func (s *ManifestDeployerSuite) assertCharm(c *gc.C, revision int, content ...ft.Entry) {
	url, err := charm.ReadCharmURL(filepath.Join(s.targetPath, ".juju-charm"))
	c.Assert(err, gc.IsNil)
	c.Assert(url, gc.DeepEquals, charmURL(revision))
	ft.Entries(content).Check(c, s.targetPath)
}
func (s *ManifestDeployerSuite) addCharm(c *gc.C, revision int, content ...ft.Entry) charm.BundleInfo {
	return s.bundles.AddCustomBundle(c, charmURL(revision), func(path string) {
		ft.Entries(content).Create(c, path)
	})
}