// SetupTestGrid creates a new grid for testing purposes.
// Select the number of hosts to create.
// Call (TestGrid).Cleanup() when done.
func SetupTestGrid(n int) (*TestGrid, error) {
	hosts, listeners, err := getHosts(n)
	if err != nil {
		return nil, err
	}
	dialer := &net.Dialer{
		Timeout: 5 * time.Second,
	}
	var res TestGrid
	res.Hosts = hosts
	ready := make(chan struct{})
	ctx, cancel := context.WithCancel(context.Background())