func loadState(backend state.Backend) (*state.State, error) {
if !osutil.FileExists(dirs.SnapStateFile) {
// fail fast, mostly interesting for tests, this dir is setup
// by the snapd package
stateDir := filepath.Dir(dirs.SnapStateFile)
if !osutil.IsDirectory(stateDir) {
return nil, fmt.Errorf("fatal: directory %q must be present", stateDir)
}
s := state.New(backend)
patch.Init(s)
return s, nil
}
r, err := os.Open(dirs.SnapStateFile)
if err != nil {
return nil, fmt.Errorf("cannot read the state file: %s", err)
}
defer r.Close()
s, err := state.ReadState(backend, r)
if err != nil {
return nil, err
}
// one-shot migrations
err = patch.Apply(s)
if err != nil {
return nil, err
}
return s, nil
}
func (s *patchSuite) TestInit(c *C) {
restore := patch.Mock(2, nil)
defer restore()
st := state.New(nil)
patch.Init(st)
st.Lock()
defer st.Unlock()
var patchLevel int
err := st.Get("patch-level", &patchLevel)
c.Assert(err, IsNil)
c.Check(patchLevel, Equals, 2)
}