generate: Run encoder output through decoder in tests

generate/misc_test.go

@@ -78,6 +78,42 @@ func testGenerateRun(test *testing.T, protocol *Protocol, title, imports, testCa
 				log.Fatalln("not equal")
 			}
 		}
+
+		// TODO: possibly combine the two above functions into this one,
+		// also take a data parameter here (snake)
+		func testEncodeDecode(message Message, data tu.Snake) {buffer := bytes.Buffer { }
+			log.Println("encoding:")
+			encoder := tape.NewEncoder(&buffer)
+			n, err := message.Encode(encoder)
+			if err != nil { log.Fatalf("at %d: %v\n", n, err) }
+			encoder.Flush()
+			got := buffer.Bytes()
+			log.Printf("got:     [%s]", tu.HexBytes(got))
+			log.Println("correct:", data)
+			if n != len(got) {
+				log.Fatalf("n incorrect: %d != %d\n", n, len(got))
+			}
+			if ok, n := data.Check(got); !ok {
+				log.Fatalln("not equal at", n)
+			}
+		
+			log.Println("decoding:")
+			destination := reflect.New(reflect.ValueOf(message).Elem().Type()).Interface().(Message)
+			flat := data.Flatten()
+			log.Println("before: ", destination)
+			decoder := tape.NewDecoder(bytes.NewBuffer(flat))
+			n, err = destination.Decode(decoder)
+			if err != nil { log.Fatalf("at %d: %v\n", n, err) }
+			log.Println("got:    ", destination)
+			log.Println("correct:", message)
+			if n != len(flat) {
+				log.Fatalf("n incorrect: %d != %d\n", n, len(flat))
+			}
+			if !reflect.DeepEqual(destination, message) {
+				log.Fatalln("not equal")
+			}
+			
+		}
 		`
 	fmt.Fprintf(
 		mainFile, "package main\n%s\nfunc main() {\n%s\n%s\n%s\n}\n%s",