package layer import ( "io" "testing" "github.com/docker/distribution/digest" ) func TestEmptyLayer(t *testing.T) { if EmptyLayer.ChainID() != ChainID(DigestSHA256EmptyTar) { t.Fatal("wrong ID for empty layer") } if EmptyLayer.DiffID() != DigestSHA256EmptyTar { t.Fatal("wrong DiffID for empty layer") } if EmptyLayer.Parent() != nil { t.Fatal("expected no parent for empty layer") } if size, err := EmptyLayer.Size(); err != nil || size != 0 { t.Fatal("expected zero size for empty layer") } if diffSize, err := EmptyLayer.DiffSize(); err != nil || diffSize != 0 { t.Fatal("expected zero diffsize for empty layer") } tarStream, err := EmptyLayer.TarStream() if err != nil { t.Fatalf("error streaming tar for empty layer: %v", err) } digester := digest.Canonical.New() _, err = io.Copy(digester.Hash(), tarStream) if err != nil { t.Fatalf("error hashing empty tar layer: %v", err) } if digester.Digest() != digest.Digest(DigestSHA256EmptyTar) { t.Fatal("empty layer tar stream hashes to wrong value") } }