Add detailed assertion output for some resolver tests, skip IPv4+IPv6 test

Author: murgatroid99

packages/grpc-js/test/test-resolver.ts

@@ -24,7 +24,7 @@ import * as resolver_uds from '../src/resolver-uds';
 import * as resolver_ip from '../src/resolver-ip';
 import { ServiceConfig } from '../src/service-config';
 import { StatusObject } from '../src/call-stream';
-import { SubchannelAddress, isTcpSubchannelAddress } from "../src/subchannel-address";
+import { SubchannelAddress, isTcpSubchannelAddress, subchannelAddressToString } from "../src/subchannel-address";
 import { parseUri, GrpcUri } from '../src/uri-parser';
 
 describe('Name Resolver', () => {
@@ -223,7 +223,7 @@ describe('Name Resolver', () => {
                 isTcpSubchannelAddress(addr) &&
                 addr.host === '127.0.0.1' &&
                 addr.port === 443
-            )
+            ), `None of [${addressList.map(addr => subchannelAddressToString(addr))}] matched '127.0.0.1:443'`
           );
           done();
         },
@@ -263,7 +263,10 @@ describe('Name Resolver', () => {
       const resolver = resolverManager.createResolver(target, listener, {});
       resolver.updateResolution();
     });
-    it('Should resolve a DNS name to IPv4 and IPv6 addresses', done => {
+    /* This DNS name resolves to only the IPv4 address on Windows, and only the
+     * IPv6 address on Mac. There is no result that we can consistently test
+     * for here. */
+    it.skip('Should resolve a DNS name to IPv4 and IPv6 addresses', done => {
       const target = resolverManager.mapUriDefaultScheme(parseUri('loopback46.unittest.grpc.io')!)!;
       const listener: resolverManager.ResolverListener = {
         onSuccessfulResolution: (
@@ -279,7 +282,7 @@ describe('Name Resolver', () => {
                 isTcpSubchannelAddress(addr) &&
                 addr.host === '127.0.0.1' &&
                 addr.port === 443
-            )
+            ), `None of [${addressList.map(addr => subchannelAddressToString(addr))}] matched '127.0.0.1:443'`
           );
           /* TODO(murgatroid99): check for IPv6 result, once we can get that
            * consistently */