feat(tools): Add a simple MockIndexer helper for IRC announcing and indexing (#555)

* Add a simple SelfIndexer for IRC announcing and indexing

* Rename to MockIndexer

* fix: close file after reading

test/mockindexer/irc/server.go

@@ -0,0 +1,50 @@
+package irc
+
+import (
+	"fmt"
+	"log"
+	"net"
+)
+
+type Server struct {
+	listener net.Listener
+	clients  []*Client
+	options  *ServerOptions
+}
+
+type ServerOptions struct {
+	BotName string
+	Channel string
+}
+
+func NewServer(options *ServerOptions) (*Server, error) {
+	listener, err := net.Listen("tcp", "localhost:6697")
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &Server{
+		listener: listener,
+		options:  options,
+	}, nil
+}
+
+func (s *Server) Run() {
+	for {
+		conn, err := s.listener.Accept()
+
+		if err != nil {
+			log.Printf("Failed accept: %v", err)
+			continue
+		}
+
+		s.clients = append(s.clients, NewClient(conn, s.options.BotName, s.options.Channel))
+	}
+}
+
+func (s *Server) SendAll(line string) {
+	for _, client := range s.clients {
+		client.writer <- fmt.Sprintf(":%s PRIVMSG %s :%s", s.options.BotName, s.options.Channel, line)
+	}
+}