test: de-flake test-dns-idna2008.js

* use known well-behaved DNS server
* force pass on ESERVFAIL
PR-URL: #26473Fixes: #25870
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

Author: refack

test/internet/test-dns-idna2008.js

@@ -11,23 +11,41 @@
 const{ mustCall }=require('../common');
 constassert=require('assert');
 constdns=require('dns');
+const{ addresses }=require('../common/internet');
 
-const[host,expectedAddress]=['straße.de','81.169.145.78'];
+constfixture={
+hostname: 'straße.de',
+expectedAddress: '81.169.145.78',
+dnsServer: addresses.DNS4_SERVER
+};
 
-dns.lookup(host,mustCall((err,address)=>{
+// Explicitly use well behaved DNS servers that are known to be able to resolve
+// the query (which is a.k.a xn--strae-oqa.de).
+dns.setServers([fixture.dnsServer]);
+
+dns.lookup(fixture.hostname,mustCall((err,address)=>{
+if(err&&err.errno==='ESERVFAIL'){
+assert.ok(err.message.includes('queryA ESERVFAIL straße.de'));
+return;
+}
 assert.ifError(err);
-assert.strictEqual(address,expectedAddress);
+assert.strictEqual(address,fixture.expectedAddress);
 }));
 
-dns.promises.lookup(host).then(mustCall(({ address })=>{
-assert.strictEqual(address,expectedAddress);
+dns.promises.lookup(fixture.hostname).then(mustCall(({ address })=>{
+assert.strictEqual(address,fixture.expectedAddress);
+}).catch((err)=>{
+if(err&&err.errno==='ESERVFAIL'){
+assert.ok(err.message.includes('queryA ESERVFAIL straße.de'));
+}
 }));
 
-dns.resolve4(host,mustCall((err,addresses)=>{
+dns.resolve4(fixture.hostname,mustCall((err,addresses)=>{
 assert.ifError(err);
-assert.deepStrictEqual(addresses,[expectedAddress]);
+assert.deepStrictEqual(addresses,[fixture.expectedAddress]);
 }));
 
-newdns.promises.Resolver().resolve4(host).then(mustCall((addresses)=>{
-assert.deepStrictEqual(addresses,[expectedAddress]);
+constp=newdns.promises.Resolver().resolve4(fixture.hostname);
+p.then(mustCall((addresses)=>{
+assert.deepStrictEqual(addresses,[fixture.expectedAddress]);
 }));