Fix nickname error responses to match RFC

src/server.js

@@ -57,12 +57,12 @@ server.create = function create(config = {}) {
                                 user.setNickname(nickname)
                                 userlist[user.nickname] = user
                             } else {
-                                socket.write(ERR_NICKNAMEINUSE, " nickname in use")
+                                socket.write(`:irc.example.com ${ERR_NICKNAMEINUSE} ${nickname} :Nickname is already in use`, 'ascii')
                             }
 
 
                         } else {
-                            socket.write(ERR_NONICKNAMEGIVEN, "ERROR: NO NICKNAME PROVIDED")
+                            socket.write(`:irc.example.com ${ERR_NONICKNAMEGIVEN} :No nickname given`, 'ascii')
                         }
 
                         break;

test/command_nick.js

@@ -31,7 +31,7 @@ describe("NICK already registered", function () {
         }
         let mockedSock2 = new EventEmitter()
         mockedSock2.write = function (data) {
-            assert.equal(data.toString("ascii"), "433")
+            assert.equal(data.toString("ascii"), ":irc.example.com 433 some_nick :Nickname is already in use")
             done()
         }
         mockedSock2.destroy = function () {
@@ -49,7 +49,7 @@ describe("NICK no NICK given", function () {
         const server = IRCServer.create()
         let mockedSock = new EventEmitter()
         mockedSock.write = function (data) {
-            assert.equal(data.toString("ascii"), "431")
+            assert.equal(data.toString("ascii"), ":irc.example.com 431 :No nickname given")
             done()
         }
         mockedSock.destroy = function () {