package webrtc

import (
	"net"
	"testing"
)

// TestAlloc_ReturnsRebindablePort exercises the alloc/close/rebind
// sequence 100 times. If a fast rebind race existed in normal
// conditions, this would surface it.
func TestAlloc_ReturnsRebindablePort(t *testing.T) {
	for i := 0; i < 100; i++ {
		p, err := Alloc()
		if err != nil {
			t.Fatalf("iter %d: Alloc: %v", i, err)
		}
		if p == 0 {
			t.Fatalf("iter %d: expected non-zero port", i)
		}
		c, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: p})
		if err != nil {
			t.Fatalf("iter %d: rebind port %d: %v", i, p, err)
		}
		c.Close()
	}
}

// TestAlloc_DistinctPorts confirms the OS doesn't hand us the same
// ephemeral port twice in quick succession (it shouldn't — the socket
// is briefly held in the bound state on close).
func TestAlloc_DistinctPorts(t *testing.T) {
	seen := map[int]bool{}
	for i := 0; i < 10; i++ {
		p, err := Alloc()
		if err != nil {
			t.Fatal(err)
		}
		if seen[p] {
			t.Fatalf("duplicate port %d", p)
		}
		seen[p] = true
	}
}