func (ks *DSSuite) TestOpen(c *C) {
	_, err := fs.NewDatastore("/tmp/foo/bar/baz")
	c.Assert(err, Not(Equals), nil)

	// setup ds
	_, err = fs.NewDatastore(ks.dir)
	c.Assert(err, Equals, nil)
}
func (ks *DSSuite) SetUpTest(c *C) {
	ks.dir = c.MkDir()
	ks.ds, _ = fs.NewDatastore(ks.dir)
}