package network

import (
	"strings"
	"testing"
)

func TestPersistencePreservesHostConfiguration(t *testing.T) {
	original := "auto lo\niface lo inet loopback\nauto eth0\niface eth0 inet dhcp\n    mtu 1450\n    post-up ip route add 10.0.0.0/8 via 192.0.2.1\n"
	ips := map[string][]string{"eth0": {"192.0.2.5/24", "2001:db8::5/64"}}
	updated := withSourceInclude(withManagedAddresses(original, ips))
	for _, line := range strings.Split(strings.TrimSpace(original), "\n") {
		if !strings.Contains(updated, line) {
			t.Fatalf("lost host setting: %s", line)
		}
	}
	if strings.Count(updated, "iface eth0") != 1 || strings.Count(updated, "source /etc/network/interfaces.d/*") != 1 {
		t.Fatal(updated)
	}
	if !strings.Contains(updated, "2001:db8::5/64") {
		t.Fatal("IPv6 address lost")
	}
	if again := withSourceInclude(withManagedAddresses(updated, ips)); again != updated {
		t.Fatal("repeated persistence changed configuration")
	}
	removed := withManagedAddresses(updated, map[string][]string{})
	if strings.Contains(removed, "192.0.2.5") || !strings.Contains(removed, "inet dhcp") {
		t.Fatal("address deletion touched host config or retained removed address")
	}
}