b",  }  ref := createRef(t, cm, ch)   dgst, err := Checksum(context.TODO(), ref, "d0/def/foo", true)  require.NoError(t, err)  require.Equal(t, dgstFileData0, dgst)   dgst, err = Checksum(context.TODO(), ref, "d0/def/foo", true)  require.NoError(t, err)  require.Equal(t, dgstFileData0, dgst)   err = ref.Release(context.TODO())  require.NoError(t, err) }  func TestSymlink