From 0778274b72436275893ee37f8db6dd8ad9ad83c6 Mon Sep 17 00:00:00 2001
From: Armin Braun <me@obrown.io>
Date: Wed, 29 Jul 2020 13:16:12 +0200
Subject: [PATCH] Fix IPV6 Scope Id in InetAddressesTests (#60368) (#60369)

Follow up to #60360, turns out at times the name of an interface that isn't loopback is not a valid scope id.
---
 .../common/network/InetAddressesTests.java          | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/server/src/test/java/org/elasticsearch/common/network/InetAddressesTests.java b/server/src/test/java/org/elasticsearch/common/network/InetAddressesTests.java
index 7922d3eadc4..0fc03040e6d 100644
--- a/server/src/test/java/org/elasticsearch/common/network/InetAddressesTests.java
+++ b/server/src/test/java/org/elasticsearch/common/network/InetAddressesTests.java
@@ -23,6 +23,7 @@ import org.hamcrest.Matchers;
 import java.net.InetAddress;
 import java.net.NetworkInterface;
 import java.net.UnknownHostException;
+import java.util.Enumeration;
 
 public class InetAddressesTests extends ESTestCase {
     public void testForStringBogusInput() {
@@ -130,7 +131,17 @@ public class InetAddressesTests extends ESTestCase {
     }
 
     public void testForStringIPv6WithScopeIdInput() throws java.io.IOException {
-        String ipStr = "0:0:0:0:0:0:0:1%" + NetworkInterface.getNetworkInterfaces().nextElement().getName();
+        final Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+        String scopeId = null;
+        while (interfaces.hasMoreElements()) {
+            final NetworkInterface nint = interfaces.nextElement();
+            if (nint.isLoopback()) {
+                scopeId = nint.getName();
+                break;
+            }
+        }
+        assertNotNull(scopeId);
+        String ipStr = "0:0:0:0:0:0:0:1%" + scopeId;
         InetAddress ipv6Addr = InetAddress.getByName(ipStr);
         assertEquals(ipv6Addr, InetAddresses.forString(ipStr));
         assertTrue(InetAddresses.isInetAddress(ipStr));