CNPeer/Service refactor

- each CNPeer is given a unique chan *protocol.Event to pass events to
the service.handleEvents() loop. this is now passed to CNPeer.Handler()
as opposed to NewCNPeer().
- service has basically been rewritten. handleEvents() main loop uses
reflect.SelectCase() now to handle all of the eRecv channels for each
peer
- new protocol Event type: EVENT_CLIENT_CONNECT
- Added service_test.go; blackbox-styled testing like the others.
TestService() starts a service and spins up  a bunch of dummy peers
and verifies that each packet sent causes the corresponding packet
handler to be called.

internal/service/service_test.go

@@ -0,0 +1,91 @@
+package service_test
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/CPunch/gopenfusion/internal/protocol"
+	"github.com/CPunch/gopenfusion/internal/service"
+)
+
+var (
+	srvc     *service.Service
+	srvcPort int
+)
+
+const (
+	timeout       = 5
+	maxDummyPeers = 5
+)
+
+func waitWithTimeout(wg *sync.WaitGroup, seconds int) bool {
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		wg.Wait()
+	}()
+
+	select {
+	case <-done:
+		return true
+	case <-time.After(time.Duration(seconds) * time.Second):
+		return false
+	}
+}
+
+func TestMain(m *testing.M) {
+	var err error
+	srvcPort, err = service.RandomPort()
+	if err != nil {
+		panic(err)
+	}
+
+	srvc = service.NewService("TEST", srvcPort)
+	os.Exit(m.Run())
+}
+
+func TestService(t *testing.T) {
+	// waitgroup to wait for test packet handler to be called
+	wg := sync.WaitGroup{}
+
+	srvc.AddPacketHandler(0x1234, func(peer *protocol.CNPeer, uData interface{}, pkt protocol.Packet) error {
+		wg.Done()
+		return nil
+	})
+
+	go func() {
+		if err := srvc.Start(); err != nil {
+			t.Error(err)
+		}
+	}()
+
+	// wait for service to start
+	<-srvc.Started()
+	wg.Add(maxDummyPeers)
+	for i := 0; i < maxDummyPeers; i++ {
+		go func() {
+			// make dummy client
+			conn, err := net.Dial("tcp", fmt.Sprintf("127.0.0.1:%d", srvcPort))
+			if err != nil {
+				t.Error(err)
+			}
+
+			peer := protocol.NewCNPeer(conn)
+			defer peer.Kill()
+			// send dummy packet
+			if err := peer.Send(0x1234); err != nil {
+				t.Error(err)
+			}
+		}()
+	}
+
+	if !waitWithTimeout(&wg, timeout) {
+		t.Error("timeout waiting for packet handler to be called")
+	}
+	srvc.Stop()
+	<-srvc.Stopped()
+}