fixup! sphinx_test: onion message packet creation

Author: gijswijs

sphinx_test.go

@@ -342,6 +342,14 @@ func TestBolt4Packet(t *testing.T) {
 	}
 }
 
+// TestTLVPayloadMessagePacket tests the creation and encoding of an onion
+// message packet that uses a TLV payload for each hop in the route. This test
+// uses the test vectors defined in the BOLT 4 specification. The test reads a
+// JSON file containing a predefined route, session key, and the expected final
+// onion packet. It then constructs the route hop-by-hop, manually creating the
+// TLV payload for each, before creating a new onion packet with NewOnionPacket.
+// The test concludes by asserting that the newly encoded packet is identical to
+// the one specified in the test vector.
 func TestTLVPayloadMessagePacket(t *testing.T) {
 	t.Parallel()