package firewall

import (
	"strings"
	"testing"
)

func TestBuildNATRuleLines_InterfaceList(t *testing.T) {
	rule := NATRule{
		ID:               "nat-test-1",
		Order:            1,
		Chain:            "srcnat",
		Action:           "masquerade",
		OutInterfaceList: "WAN",
		Disabled:         false,
	}

	lines := buildNATRuleLines(rule)
	if len(lines) == 0 {
		t.Fatalf("expected non-empty lines for WAN interface list, got 0")
	}

	for _, l := range lines {
		if !strings.Contains(l, "-j MASQUERADE") {
			t.Errorf("line missing -j MASQUERADE: %s", l)
		}
		if !strings.Contains(l, "-o ") {
			t.Errorf("expected -o flag in expanded NAT rule, got: %s", l)
		}
	}
}