package layer // import "github.com/docker/docker/layer" import ( "io" "testing" digest "github.com/opencontainers/go-digest" ) func TestEmptyLayer(t *testing.T) { if EmptyLayer.ChainID() != ChainID(DigestSHA256EmptyTar) { t.Fatal("wrong ChainID 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") } meta, err := EmptyLayer.Metadata() if len(meta) != 0 || err != nil { t.Fatal("expected zero length metadata for empty layer") } tarStream, err := EmptyLayer.TarStream() if err != nil { t.Fatalf("error streaming tar for empty layer: %v", err) } digester := digest.Canonical.Digester() _, 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") } }