update demo to test valid type with no data

agent/grpc-external/services/resource/write_test.go

@@ -680,6 +680,21 @@ func TestWrite_NonCASUpdate_Retry(t *testing.T) {
 	require.NoError(t, <-errCh)
 }
 
+func TestWrite_NoData(t *testing.T) {
+	server := testServer(t)
+	client := testClient(t, server)
+
+	demo.RegisterTypes(server.Registry)
+
+	res, err := demo.GenerateV1Concept("jazz")
+	require.NoError(t, err)
+
+	rsp, err := client.Write(testContext(t), &pbresource.WriteRequest{Resource: res})
+	require.NoError(t, err)
+	require.NotEmpty(t, rsp.Resource.Version)
+	require.Equal(t, rsp.Resource.Id.Name, "jazz")
+}
+
 func TestWrite_Owner_Immutable(t *testing.T) {
 	// Use of proto.Equal(..) in implementation covers all permutations
 	// (nil -> non-nil, non-nil -> nil, owner1 -> owner2) so only the first one

internal/resource/demo/demo.go

@@ -44,6 +44,13 @@ var (
 		Kind:         "Album",
 	}
 
+	// TypeV1Concept represents an abstract concept that can be associated with any other resource.
+	TypeV1Concept = &pbresource.Type{
+		Group:        "demo",
+		GroupVersion: "v1",
+		Kind:         "Concept",
+	}
+
 	// TypeV2Artist represents a musician or group of musicians.
 	TypeV2Artist = &pbresource.Type{
 		Group:        "demo",
@@ -159,6 +166,17 @@ func RegisterTypes(r resource.Registry) {
 		},
 	})
 
+	r.Register(resource.Registration{
+		Type:  TypeV1Concept,
+		Proto: &pbdemov1.Concept{},
+		Scope: resource.ScopeNamespace,
+		ACLs: &resource.ACLHooks{
+			Read:  readACL,
+			Write: writeACL,
+			List:  makeListACL(TypeV1Concept),
+		},
+	})
+
 	r.Register(resource.Registration{
 		Type:  TypeV2Artist,
 		Proto: &pbdemov2.Artist{},
@@ -204,6 +222,21 @@ func GenerateV1RecordLabel(name string) (*pbresource.Resource, error) {
 	}, nil
 }
 
+// GenerateV1Concept generates a named concept resource.
+func GenerateV1Concept(name string) (*pbresource.Resource, error) {
+	return &pbresource.Resource{
+		Id: &pbresource.ID{
+			Type:    TypeV1Concept,
+			Tenancy: resource.DefaultPartitionedTenancy(),
+			Name:    name,
+		},
+		Data: nil,
+		Metadata: map[string]string{
+			"generated_at": time.Now().Format(time.RFC3339),
+		},
+	}, nil
+}
+
 // GenerateV2Artist generates a random Artist resource.
 func GenerateV2Artist() (*pbresource.Resource, error) {
 	adjective := adjectives[rand.Intn(len(adjectives))]

proto/private/pbdemo/v1/demo.proto

@@ -41,3 +41,5 @@ message Album {
   bool critically_acclaimed = 3;
   repeated string tracks = 4;
 }
+
+message Concept {}