func (s *S) TestCustomDialNew(c *C) {
	dials := make(chan bool, 16)
	dial := func(addr *mgo.ServerAddr) (net.Conn, error) {
		dials <- true
		if addr.TCPAddr().Port == 40012 {
			c.Check(addr.String(), Equals, "localhost:40012")
		}
		return net.DialTCP("tcp", nil, addr.TCPAddr())
	}
	info := mgo.DialInfo{
		Addrs:      []string{"localhost:40012"},
		DialServer: dial,
	}

	// Use hostname here rather than IP, to make things trickier.
	session, err := mgo.DialWithInfo(&info)
	c.Assert(err, IsNil)
	defer session.Close()

	const N = 3
	for i := 0; i < N; i++ {
		select {
		case <-dials:
		case <-time.After(5 * time.Second):
			c.Fatalf("expected %d dials, got %d", N, i)
		}
	}
	select {
	case <-dials:
		c.Fatalf("got more dials than expected")
	case <-time.After(100 * time.Millisecond):
	}
}
func (s *S) TestCustomDialOld(c *C) {
	dials := make(chan bool, 16)
	dial := func(addr net.Addr) (net.Conn, error) {
		tcpaddr, ok := addr.(*net.TCPAddr)
		if !ok {
			return nil, fmt.Errorf("unexpected address type: %T", addr)
		}
		dials <- true
		return net.DialTCP("tcp", nil, tcpaddr)
	}
	info := mgo.DialInfo{
		Addrs: []string{"localhost:40012"},
		Dial:  dial,
	}

	// Use hostname here rather than IP, to make things trickier.
	session, err := mgo.DialWithInfo(&info)
	c.Assert(err, IsNil)
	defer session.Close()

	const N = 3
	for i := 0; i < N; i++ {
		select {
		case <-dials:
		case <-time.After(5 * time.Second):
			c.Fatalf("expected %d dials, got %d", N, i)
		}
	}
	select {
	case <-dials:
		c.Fatalf("got more dials than expected")
	case <-time.After(100 * time.Millisecond):
	}
}