chore: fix Test_Node_Encode

pkg/trie/node/encode.go

@@ -16,16 +16,16 @@ import (
 // of this package, and specified in the Polkadot spec at
 // https://spec.polkadot.network/#sect-state-storage
 func (n *Node) Encode(buffer Buffer) (err error) {
+	if n == nil {
+		_, err = buffer.Write([]byte{emptyVariant.bits})
+		return err
+	}
+
 	err = encodeHeader(n, n.MustBeHashed, buffer)
 	if err != nil {
 		return fmt.Errorf("cannot encode header: %w", err)
 	}
 
-	if n == nil {
-		// only encode the empty variant byte header
-		return nil
-	}
-
 	keyLE := codec.NibblesToKeyLE(n.PartialKey)
 	_, err = buffer.Write(keyLE)
 	if err != nil {
@@ -55,7 +55,7 @@ func (n *Node) Encode(buffer Buffer) (err error) {
 
 			_, err = buffer.Write(hashedValue.ToBytes())
 			if err != nil {
-				return fmt.Errorf("scale encoding storage value: %w", err)
+				return fmt.Errorf("writing hashed storage value: %w", err)
 			}
 		default:
 			encoder := scale.NewEncoder(buffer)

pkg/trie/node/encode_test.go

@@ -136,7 +136,7 @@ func Test_Node_Encode(t *testing.T) {
 				PartialKey:    []byte{1, 2, 3},
 				StorageValue:  largeValue,
 				IsHashedValue: true,
-				MustBeHashed:  false,
+				MustBeHashed:  true,
 			},
 			writes: []writeCall{
 				{
@@ -151,7 +151,7 @@ func Test_Node_Encode(t *testing.T) {
 				},
 			},
 			wrappedErr: errTest,
-			errMessage: "encoding hashed storage value: test error",
+			errMessage: "writing hashed storage value: test error",
 		},
 		"branch_header_encoding_error": {
 			node: &Node{

pkg/trie/node/header.go

@@ -11,11 +11,6 @@ import (
 
 // encodeHeader writes the encoded header for the node.
 func encodeHeader(node *Node, isHashedValue bool, writer io.Writer) (err error) {
-	if node == nil {
-		_, err = writer.Write([]byte{emptyVariant.bits})
-		return err
-	}
-
 	partialKeyLength := len(node.PartialKey)
 	if partialKeyLength > int(maxPartialKeyLength) {
 		panic(fmt.Sprintf("partial key length is too big: %d", partialKeyLength))