Merge pull request #1 from owtaylor/oci-media-types

Handle OCI manifests and image indexes without a media type

Signed-off-by: Mike Brown <brownwm@us.ibm.com>

manifest/manifestlist/manifestlist.go

@@ -38,6 +38,13 @@ func init() {
 			return nil, distribution.Descriptor{}, err
 		}
 
+		if m.MediaType != MediaTypeManifestList {
+			err = fmt.Errorf("mediaType in manifest list should be '%s' not '%s'",
+				MediaTypeManifestList, m.MediaType)
+
+			return nil, distribution.Descriptor{}, err
+		}
+
 		dgst := digest.FromBytes(b)
 		return m, distribution.Descriptor{Digest: dgst, Size: int64(len(b)), MediaType: MediaTypeManifestList}, err
 	}
@@ -53,6 +60,13 @@ func init() {
 			return nil, distribution.Descriptor{}, err
 		}
 
+		if m.MediaType != "" && m.MediaType != v1.MediaTypeImageIndex {
+			err = fmt.Errorf("if present, mediaType in image index should be '%s' not '%s'",
+				v1.MediaTypeImageIndex, m.MediaType)
+
+			return nil, distribution.Descriptor{}, err
+		}
+
 		dgst := digest.FromBytes(b)
 		return m, distribution.Descriptor{Digest: dgst, Size: int64(len(b)), MediaType: v1.MediaTypeImageIndex}, err
 	}
@@ -130,15 +144,23 @@ type DeserializedManifestList struct {
 // DeserializedManifestList which contains the resulting manifest list
 // and its JSON representation.
 func FromDescriptors(descriptors []ManifestDescriptor) (*DeserializedManifestList, error) {
-	var m ManifestList
+	var mediaType string
 	if len(descriptors) > 0 && descriptors[0].Descriptor.MediaType == v1.MediaTypeImageManifest {
-		m = ManifestList{
-			Versioned: OCISchemaVersion,
-		}
+		mediaType = v1.MediaTypeImageIndex
 	} else {
-		m = ManifestList{
-			Versioned: SchemaVersion,
-		}
+		mediaType = MediaTypeManifestList
+	}
+
+	return FromDescriptorsWithMediaType(descriptors, mediaType)
+}
+
+// For testing purposes, it's useful to be able to specify the media type explicitly
+func FromDescriptorsWithMediaType(descriptors []ManifestDescriptor, mediaType string) (*DeserializedManifestList, error) {
+	m := ManifestList{
+		Versioned: manifest.Versioned{
+			SchemaVersion: 2,
+			MediaType:     mediaType,
+		},
 	}
 
 	m.Manifests = make([]ManifestDescriptor, len(descriptors), len(descriptors))
@@ -183,5 +205,12 @@ func (m *DeserializedManifestList) MarshalJSON() ([]byte, error) {
 // Payload returns the raw content of the manifest list. The contents can be
 // used to calculate the content identifier.
 func (m DeserializedManifestList) Payload() (string, []byte, error) {
-	return m.MediaType, m.canonical, nil
+	var mediaType string
+	if m.MediaType == "" {
+		mediaType = v1.MediaTypeImageIndex
+	} else {
+		mediaType = m.MediaType
+	}
+
+	return mediaType, m.canonical, nil
 }

manifest/manifestlist/manifestlist_test.go

@@ -38,7 +38,7 @@ var expectedManifestListSerialization = []byte(`{
    ]
 }`)
 
-func TestManifestList(t *testing.T) {
+func makeTestManifestList(t *testing.T, mediaType string) ([]ManifestDescriptor, *DeserializedManifestList) {
 	manifestDescriptors := []ManifestDescriptor{
 		{
 			Descriptor: distribution.Descriptor{
@@ -65,11 +65,16 @@ func TestManifestList(t *testing.T) {
 		},
 	}
 
-	deserialized, err := FromDescriptors(manifestDescriptors)
+	deserialized, err := FromDescriptorsWithMediaType(manifestDescriptors, mediaType)
 	if err != nil {
 		t.Fatalf("error creating DeserializedManifestList: %v", err)
 	}
 
+	return manifestDescriptors, deserialized
+}
+
+func TestManifestList(t *testing.T) {
+	manifestDescriptors, deserialized := makeTestManifestList(t, MediaTypeManifestList)
 	mediaType, canonical, _ := deserialized.Payload()
 
 	if mediaType != MediaTypeManifestList {
@@ -160,7 +165,7 @@ var expectedOCIImageIndexSerialization = []byte(`{
    ]
 }`)
 
-func TestOCIImageIndex(t *testing.T) {
+func makeTestOCIImageIndex(t *testing.T, mediaType string) ([]ManifestDescriptor, *DeserializedManifestList) {
 	manifestDescriptors := []ManifestDescriptor{
 		{
 			Descriptor: distribution.Descriptor{
@@ -196,11 +201,17 @@ func TestOCIImageIndex(t *testing.T) {
 		},
 	}
 
-	deserialized, err := FromDescriptors(manifestDescriptors)
+	deserialized, err := FromDescriptorsWithMediaType(manifestDescriptors, mediaType)
 	if err != nil {
 		t.Fatalf("error creating DeserializedManifestList: %v", err)
 	}
 
+	return manifestDescriptors, deserialized
+}
+
+func TestOCIImageIndex(t *testing.T) {
+	manifestDescriptors, deserialized := makeTestOCIImageIndex(t, v1.MediaTypeImageIndex)
+
 	mediaType, canonical, _ := deserialized.Payload()
 
 	if mediaType != v1.MediaTypeImageIndex {
@@ -241,3 +252,54 @@ func TestOCIImageIndex(t *testing.T) {
 		}
 	}
 }
+
+func mediaTypeTest(t *testing.T, contentType string, mediaType string, shouldError bool) {
+	var m *DeserializedManifestList
+	if contentType == MediaTypeManifestList {
+		_, m = makeTestManifestList(t, mediaType)
+	} else {
+		_, m = makeTestOCIImageIndex(t, mediaType)
+	}
+
+	_, canonical, err := m.Payload()
+	if err != nil {
+		t.Fatalf("error getting payload, %v", err)
+	}
+
+	unmarshalled, descriptor, err := distribution.UnmarshalManifest(
+		contentType,
+		canonical)
+
+	if shouldError {
+		if err == nil {
+			t.Fatalf("bad content type should have produced error")
+		}
+	} else {
+		if err != nil {
+			t.Fatalf("error unmarshaling manifest, %v", err)
+		}
+
+		asManifest := unmarshalled.(*DeserializedManifestList)
+		if asManifest.MediaType != mediaType {
+			t.Fatalf("Bad media type '%v' as unmarshalled", asManifest.MediaType)
+		}
+
+		if descriptor.MediaType != contentType {
+			t.Fatalf("Bad media type '%v' for descriptor", descriptor.MediaType)
+		}
+
+		unmarshalledMediaType, _, _ := unmarshalled.Payload()
+		if unmarshalledMediaType != contentType {
+			t.Fatalf("Bad media type '%v' for payload", unmarshalledMediaType)
+		}
+	}
+}
+
+func TestMediaTypes(t *testing.T) {
+	mediaTypeTest(t, MediaTypeManifestList, "", true)
+	mediaTypeTest(t, MediaTypeManifestList, MediaTypeManifestList, false)
+	mediaTypeTest(t, MediaTypeManifestList, MediaTypeManifestList+"XXX", true)
+	mediaTypeTest(t, v1.MediaTypeImageIndex, "", false)
+	mediaTypeTest(t, v1.MediaTypeImageIndex, v1.MediaTypeImageIndex, false)
+	mediaTypeTest(t, v1.MediaTypeImageIndex, v1.MediaTypeImageIndex+"XXX", true)
+}

manifest/ocischema/builder.go

@@ -4,12 +4,13 @@ import (
 	"context"
 
 	"github.com/docker/distribution"
+	"github.com/docker/distribution/manifest"
 	"github.com/opencontainers/go-digest"
 	"github.com/opencontainers/image-spec/specs-go/v1"
 )
 
 // builder is a type for constructing manifests.
-type builder struct {
+type Builder struct {
 	// bs is a BlobService used to publish the configuration blob.
 	bs distribution.BlobService
 
@@ -22,26 +23,43 @@ type builder struct {
 
 	// Annotations contains arbitrary metadata relating to the targeted content.
 	annotations map[string]string
+
+	// For testing purposes
+	mediaType string
 }
 
 // NewManifestBuilder is used to build new manifests for the current schema
 // version. It takes a BlobService so it can publish the configuration blob
 // as part of the Build process, and annotations.
 func NewManifestBuilder(bs distribution.BlobService, configJSON []byte, annotations map[string]string) distribution.ManifestBuilder {
-	mb := &builder{
+	mb := &Builder{
 		bs:          bs,
 		configJSON:  make([]byte, len(configJSON)),
 		annotations: annotations,
+		mediaType:   v1.MediaTypeImageManifest,
 	}
 	copy(mb.configJSON, configJSON)
 
 	return mb
 }
 
+// For testing purposes, we want to be able to create an OCI image with
+// either an MediaType either empty, or with the OCI image value
+func (mb *Builder) SetMediaType(mediaType string) {
+	if mediaType != "" && mediaType != v1.MediaTypeImageManifest {
+		panic("Invalid media type for OCI image manifest")
+	}
+
+	mb.mediaType = mediaType
+}
+
 // Build produces a final manifest from the given references.
-func (mb *builder) Build(ctx context.Context) (distribution.Manifest, error) {
+func (mb *Builder) Build(ctx context.Context) (distribution.Manifest, error) {
 	m := Manifest{
-		Versioned:   SchemaVersion,
+		Versioned: manifest.Versioned{
+			SchemaVersion: 2,
+			MediaType:     mb.mediaType,
+		},
 		Layers:      make([]distribution.Descriptor, len(mb.layers)),
 		Annotations: mb.annotations,
 	}
@@ -76,12 +94,12 @@ func (mb *builder) Build(ctx context.Context) (distribution.Manifest, error) {
 }
 
 // AppendReference adds a reference to the current ManifestBuilder.
-func (mb *builder) AppendReference(d distribution.Describable) error {
+func (mb *Builder) AppendReference(d distribution.Describable) error {
 	mb.layers = append(mb.layers, d.Descriptor())
 	return nil
 }
 
 // References returns the current references added to this builder.
-func (mb *builder) References() []distribution.Descriptor {
+func (mb *Builder) References() []distribution.Descriptor {
 	return mb.layers
 }

manifest/ocischema/manifest.go

@@ -97,6 +97,11 @@ func (m *DeserializedManifest) UnmarshalJSON(b []byte) error {
 		return err
 	}
 
+	if manifest.MediaType != "" && manifest.MediaType != v1.MediaTypeImageManifest {
+		return fmt.Errorf("if present, mediaType in manifest should be '%s' not '%s'",
+			v1.MediaTypeImageManifest, manifest.MediaType)
+	}
+
 	m.Manifest = manifest
 
 	return nil
@@ -115,5 +120,5 @@ func (m *DeserializedManifest) MarshalJSON() ([]byte, error) {
 // Payload returns the raw content of the manifest. The contents can be used to
 // calculate the content identifier.
 func (m DeserializedManifest) Payload() (string, []byte, error) {
-	return m.MediaType, m.canonical, nil
+	return v1.MediaTypeImageManifest, m.canonical, nil
 }

manifest/ocischema/manifest_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"github.com/docker/distribution"
+	"github.com/docker/distribution/manifest"
 	"github.com/opencontainers/image-spec/specs-go/v1"
 )
 
@@ -36,9 +37,12 @@ var expectedManifestSerialization = []byte(`{
    }
 }`)
 
-func TestManifest(t *testing.T) {
-	manifest := Manifest{
-		Versioned: SchemaVersion,
+func makeTestManifest(mediaType string) Manifest {
+	return Manifest{
+		Versioned: manifest.Versioned{
+			SchemaVersion: 2,
+			MediaType:     mediaType,
+		},
 		Config: distribution.Descriptor{
 			Digest:      "sha256:1a9ec845ee94c202b2d5da74a24f0ed2058318bfa9879fa541efaecba272e86b",
 			Size:        985,
@@ -55,6 +59,10 @@ func TestManifest(t *testing.T) {
 		},
 		Annotations: map[string]string{"hot": "potato"},
 	}
+}
+
+func TestManifest(t *testing.T) {
+	manifest := makeTestManifest(v1.MediaTypeImageManifest)
 
 	deserialized, err := FromStruct(manifest)
 	if err != nil {
@@ -131,3 +139,46 @@ func TestManifest(t *testing.T) {
 		t.Fatalf("unexpected annotation in reference: %s", references[1].Annotations["lettuce"])
 	}
 }
+
+func mediaTypeTest(t *testing.T, mediaType string, shouldError bool) {
+	manifest := makeTestManifest(mediaType)
+
+	deserialized, err := FromStruct(manifest)
+	if err != nil {
+		t.Fatalf("error creating DeserializedManifest: %v", err)
+	}
+
+	unmarshalled, descriptor, err := distribution.UnmarshalManifest(
+		v1.MediaTypeImageManifest,
+		deserialized.canonical)
+
+	if shouldError {
+		if err == nil {
+			t.Fatalf("bad content type should have produced error")
+		}
+	} else {
+		if err != nil {
+			t.Fatalf("error unmarshaling manifest, %v", err)
+		}
+
+		asManifest := unmarshalled.(*DeserializedManifest)
+		if asManifest.MediaType != mediaType {
+			t.Fatalf("Bad media type '%v' as unmarshalled", asManifest.MediaType)
+		}
+
+		if descriptor.MediaType != v1.MediaTypeImageManifest {
+			t.Fatalf("Bad media type '%v' for descriptor", descriptor.MediaType)
+		}
+
+		unmarshalledMediaType, _, _ := unmarshalled.Payload()
+		if unmarshalledMediaType != v1.MediaTypeImageManifest {
+			t.Fatalf("Bad media type '%v' for payload", unmarshalledMediaType)
+		}
+	}
+}
+
+func TestMediaTypes(t *testing.T) {
+	mediaTypeTest(t, "", false)
+	mediaTypeTest(t, v1.MediaTypeImageManifest, false)
+	mediaTypeTest(t, v1.MediaTypeImageManifest+"XXX", true)
+}

manifest/schema2/manifest.go

@@ -116,6 +116,12 @@ func (m *DeserializedManifest) UnmarshalJSON(b []byte) error {
 		return err
 	}
 
+	if manifest.MediaType != MediaTypeManifest {
+		return fmt.Errorf("mediaType in manifest should be '%s' not '%s'",
+			MediaTypeManifest, manifest.MediaType)
+
+	}
+
 	m.Manifest = manifest
 
 	return nil

manifest/schema2/manifest_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"github.com/docker/distribution"
+	"github.com/docker/distribution/manifest"
 )
 
 var expectedManifestSerialization = []byte(`{
@@ -26,9 +27,12 @@ var expectedManifestSerialization = []byte(`{
    ]
 }`)
 
-func TestManifest(t *testing.T) {
-	manifest := Manifest{
-		Versioned: SchemaVersion,
+func makeTestManifest(mediaType string) Manifest {
+	return Manifest{
+		Versioned: manifest.Versioned{
+			SchemaVersion: 2,
+			MediaType:     mediaType,
+		},
 		Config: distribution.Descriptor{
 			Digest:    "sha256:1a9ec845ee94c202b2d5da74a24f0ed2058318bfa9879fa541efaecba272e86b",
 			Size:      985,
@@ -42,6 +46,10 @@ func TestManifest(t *testing.T) {
 			},
 		},
 	}
+}
+
+func TestManifest(t *testing.T) {
+	manifest := makeTestManifest(MediaTypeManifest)
 
 	deserialized, err := FromStruct(manifest)
 	if err != nil {
@@ -109,3 +117,46 @@ func TestManifest(t *testing.T) {
 		t.Fatalf("unexpected size in reference: %d", references[0].Size)
 	}
 }
+
+func mediaTypeTest(t *testing.T, mediaType string, shouldError bool) {
+	manifest := makeTestManifest(mediaType)
+
+	deserialized, err := FromStruct(manifest)
+	if err != nil {
+		t.Fatalf("error creating DeserializedManifest: %v", err)
+	}
+
+	unmarshalled, descriptor, err := distribution.UnmarshalManifest(
+		MediaTypeManifest,
+		deserialized.canonical)
+
+	if shouldError {
+		if err == nil {
+			t.Fatalf("bad content type should have produced error")
+		}
+	} else {
+		if err != nil {
+			t.Fatalf("error unmarshaling manifest, %v", err)
+		}
+
+		asManifest := unmarshalled.(*DeserializedManifest)
+		if asManifest.MediaType != mediaType {
+			t.Fatalf("Bad media type '%v' as unmarshalled", asManifest.MediaType)
+		}
+
+		if descriptor.MediaType != MediaTypeManifest {
+			t.Fatalf("Bad media type '%v' for descriptor", descriptor.MediaType)
+		}
+
+		unmarshalledMediaType, _, _ := unmarshalled.Payload()
+		if unmarshalledMediaType != MediaTypeManifest {
+			t.Fatalf("Bad media type '%v' for payload", unmarshalledMediaType)
+		}
+	}
+}
+
+func TestMediaTypes(t *testing.T) {
+	mediaTypeTest(t, "", true)
+	mediaTypeTest(t, MediaTypeManifest, false)
+	mediaTypeTest(t, MediaTypeManifest+"XXX", true)
+}

registry/storage/manifeststore.go

@@ -106,6 +106,18 @@ func (ms *manifestStore) Get(ctx context.Context, dgst digest.Digest, options ..
 			return ms.ocischemaHandler.Unmarshal(ctx, dgst, content)
 		case manifestlist.MediaTypeManifestList, v1.MediaTypeImageIndex:
 			return ms.manifestListHandler.Unmarshal(ctx, dgst, content)
+		case "":
+			// OCI image or image index - no media type in the content
+
+			// First see if it looks like an image index
+			res, err := ms.manifestListHandler.Unmarshal(ctx, dgst, content)
+			resIndex := res.(*manifestlist.DeserializedManifestList)
+			if err == nil && resIndex.Manifests != nil {
+				return resIndex, nil
+			}
+
+			// Otherwise, assume it must be an image manifest
+			return ms.ocischemaHandler.Unmarshal(ctx, dgst, content)
 		default:
 			return nil, distribution.ErrManifestVerification{fmt.Errorf("unrecognized manifest content type %s", versioned.MediaType)}
 		}

registry/storage/manifeststore_test.go

@@ -9,6 +9,8 @@ import (
 
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/manifest"
+	"github.com/docker/distribution/manifest/manifestlist"
+	"github.com/docker/distribution/manifest/ocischema"
 	"github.com/docker/distribution/manifest/schema1"
 	"github.com/docker/distribution/reference"
 	"github.com/docker/distribution/registry/storage/cache/memory"
@@ -17,6 +19,7 @@ import (
 	"github.com/docker/distribution/testutil"
 	"github.com/docker/libtrust"
 	"github.com/opencontainers/go-digest"
+	"github.com/opencontainers/image-spec/specs-go/v1"
 )
 
 type manifestStoreTestEnv struct {
@@ -356,6 +359,155 @@ func testManifestStorage(t *testing.T, options ...RegistryOption) {
 	}
 }
 
+func TestOCIManifestStorage(t *testing.T) {
+	testOCIManifestStorage(t, "includeMediaTypes=true", true)
+	testOCIManifestStorage(t, "includeMediaTypes=false", false)
+}
+
+func testOCIManifestStorage(t *testing.T, testname string, includeMediaTypes bool) {
+	var imageMediaType string
+	var indexMediaType string
+	if includeMediaTypes {
+		imageMediaType = v1.MediaTypeImageManifest
+		indexMediaType = v1.MediaTypeImageIndex
+	} else {
+		imageMediaType = ""
+		indexMediaType = ""
+	}
+
+	repoName, _ := reference.WithName("foo/bar")
+	env := newManifestStoreTestEnv(t, repoName, "thetag",
+		BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()),
+		EnableDelete, EnableRedirect)
+
+	ctx := context.Background()
+	ms, err := env.repository.Manifests(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Build a manifest and store it and its layers in the registry
+
+	blobStore := env.repository.Blobs(ctx)
+	builder := ocischema.NewManifestBuilder(blobStore, []byte{}, map[string]string{})
+	builder.(*ocischema.Builder).SetMediaType(imageMediaType)
+
+	// Add some layers
+	for i := 0; i < 2; i++ {
+		rs, ds, err := testutil.CreateRandomTarFile()
+		if err != nil {
+			t.Fatalf("%s: unexpected error generating test layer file", testname)
+		}
+		dgst := digest.Digest(ds)
+
+		wr, err := env.repository.Blobs(env.ctx).Create(env.ctx)
+		if err != nil {
+			t.Fatalf("%s: unexpected error creating test upload: %v", testname, err)
+		}
+
+		if _, err := io.Copy(wr, rs); err != nil {
+			t.Fatalf("%s: unexpected error copying to upload: %v", testname, err)
+		}
+
+		if _, err := wr.Commit(env.ctx, distribution.Descriptor{Digest: dgst}); err != nil {
+			t.Fatalf("%s: unexpected error finishing upload: %v", testname, err)
+		}
+
+		builder.AppendReference(distribution.Descriptor{Digest: dgst})
+	}
+
+	manifest, err := builder.Build(ctx)
+	if err != nil {
+		t.Fatalf("%s: unexpected error generating manifest: %v", testname, err)
+	}
+
+	var manifestDigest digest.Digest
+	if manifestDigest, err = ms.Put(ctx, manifest); err != nil {
+		t.Fatalf("%s: unexpected error putting manifest: %v", testname, err)
+	}
+
+	// Also create an image index that contains the manifest
+
+	descriptor, err := env.registry.BlobStatter().Stat(ctx, manifestDigest)
+	if err != nil {
+		t.Fatalf("%s: unexpected error getting manifest descriptor", testname)
+	}
+	descriptor.MediaType = v1.MediaTypeImageManifest
+
+	platformSpec := manifestlist.PlatformSpec{
+		Architecture: "atari2600",
+		OS:           "CP/M",
+	}
+
+	manifestDescriptors := []manifestlist.ManifestDescriptor{
+		manifestlist.ManifestDescriptor{
+			Descriptor: descriptor,
+			Platform:   platformSpec,
+		},
+	}
+
+	imageIndex, err := manifestlist.FromDescriptorsWithMediaType(manifestDescriptors, indexMediaType)
+	if err != nil {
+		t.Fatalf("%s: unexpected error creating image index: %v", testname, err)
+	}
+
+	var indexDigest digest.Digest
+	if indexDigest, err = ms.Put(ctx, imageIndex); err != nil {
+		t.Fatalf("%s: unexpected error putting image index: %v", testname, err)
+	}
+
+	// Now check that we can retrieve the manifest
+
+	fromStore, err := ms.Get(ctx, manifestDigest)
+	if err != nil {
+		t.Fatalf("%s: unexpected error fetching manifest: %v", testname, err)
+	}
+
+	fetchedManifest, ok := fromStore.(*ocischema.DeserializedManifest)
+	if !ok {
+		t.Fatalf("%s: unexpected type for fetched manifest", testname)
+	}
+
+	if fetchedManifest.MediaType != imageMediaType {
+		t.Fatalf("%s: unexpected MediaType for result, %s", testname, fetchedManifest.MediaType)
+	}
+
+	payloadMediaType, _, err := fromStore.Payload()
+	if err != nil {
+		t.Fatalf("%s: error getting payload %v", testname, err)
+	}
+
+	if payloadMediaType != v1.MediaTypeImageManifest {
+		t.Fatalf("%s: unexpected MediaType for manifest payload, %s", testname, payloadMediaType)
+	}
+
+	// and the image index
+
+	fromStore, err = ms.Get(ctx, indexDigest)
+	if err != nil {
+		t.Fatalf("%s: unexpected error fetching image index: %v", testname, err)
+	}
+
+	fetchedIndex, ok := fromStore.(*manifestlist.DeserializedManifestList)
+	if !ok {
+		t.Fatalf("%s: unexpected type for fetched manifest", testname)
+	}
+
+	if fetchedIndex.MediaType != indexMediaType {
+		t.Fatalf("%s: unexpected MediaType for result, %s", testname, fetchedManifest.MediaType)
+	}
+
+	payloadMediaType, _, err = fromStore.Payload()
+	if err != nil {
+		t.Fatalf("%s: error getting payload %v", testname, err)
+	}
+
+	if payloadMediaType != v1.MediaTypeImageIndex {
+		t.Fatalf("%s: unexpected MediaType for index payload, %s", testname, payloadMediaType)
+	}
+
+}
+
 // TestLinkPathFuncs ensures that the link path functions behavior are locked
 // down and implemented as expected.
 func TestLinkPathFuncs(t *testing.T) {
@@ -387,5 +539,4 @@ func TestLinkPathFuncs(t *testing.T) {
 			t.Fatalf("incorrect path returned: %q != %q", p, testcase.expected)
 		}
 	}
-
 }