diff --git a/rpc/message/test/message.go b/rpc/message/test/message.go
index df769d28..435f20af 100644
--- a/rpc/message/test/message.go
+++ b/rpc/message/test/message.go
@@ -17,6 +17,7 @@ type jsonMessage interface {
 
 type binaryMessage interface {
 	StableMarshal([]byte) []byte
+	StableSize() int
 	Unmarshal([]byte) error
 }
 
@@ -53,6 +54,11 @@ func TestRPCMessage(t *testing.T, msgGens ...func(empty bool) message.Message) {
 			}
 
 			if bm, ok := msg.(binaryMessage); ok {
+				t.Run(fmt.Sprintf("%T.StableSize() does no allocations", bm), func(t *testing.T) {
+					require.Zero(t, testing.AllocsPerRun(1000, func() {
+						_ = bm.StableSize()
+					}))
+				})
 				t.Run(fmt.Sprintf("Binary_%T", msg), func(t *testing.T) {
 					data := bm.StableMarshal(nil)