Add EIP-8 test + activate rlpx thunk test

eth.nimble

@@ -48,6 +48,7 @@ proc runP2pTests() =
       "test_discovery",
       "test_ecies",
       "test_enode",
+      "test_rlpx_thunk",
       "test_shh",
       "test_shh_connect",
       "test_protocol_handlers",

tests/p2p/test_rlpx_thunk.json

@@ -48,5 +48,8 @@
     "payload": "010a",
     "error": "RlpTypeMismatch",
     "description": "listElem to assert on not a list"
+  },
+  "devp2p hello packet version 22 + additional list elements for EIP-8": {
+    "payload": "00f87137916b6e6574682f76302e39312f706c616e39cdc5836574683dc6846d6f726b1682270fb840fda1cff674c90c9a197539fe3dfb53086ace64f83ed7c6eabec741f7f381cc803e52ab2cd55d5569bce4347107a310dfd5f88a010cd2ffd1005ca406f1842877c883666f6f836261720304"
   }
 }

tests/p2p/test_rlpx_thunk.nim

@@ -16,6 +16,10 @@ node2.startListening()
 peer = waitFor node1.rlpxConnect(newNode(initENode(node2.keys.pubKey,
                                                    node2.address)))
 
+proc testThunk(payload: openArray[byte]) =
+  var (msgId, msgData) = recvMsgMock(payload)
+  waitFor peer.invokeThunk(msgId.int, msgData)
+
 proc testPayloads(filename: string) =
   let js = json.parseFile(filename)
 
@@ -29,16 +33,20 @@ proc testPayloads(filename: string) =
         if payloadHex.isNil or payloadHex.kind != JString:
           skip()
           continue
-        if error.isNil or error.kind != JString:
+
+        let payload = hexToSeqByte(payloadHex.str)
+
+        if error.isNil:
+          testThunk(payload)
+        else:
+          if error.kind != JString:
             skip()
             continue
 
-        let payload = hexToSeqByte(payloadHex.str)
           # TODO: can I convert the error string to an Exception type at runtime?
           expect CatchableError:
             try:
-            var (msgId, msgData) = recvMsgMock(payload)
-            waitFor peer.invokeThunk(msgId.int, msgData)
+              testThunk(payload)
             except CatchableError as e:
               check: e.name == error.str
               raise