message: test: add error message to dns impl test
diff: @@ -364,17 +364,22 @@ TEST_P(DnsImplTest, LocalLookup) {
  }
  if (GetParam() == Address::IpVersion::v6) {
  - EXPECT_EQ(nullptr, resolver_->resolve("localhost", DnsLookupFamily::Auto,
  + const std::string error_msg =
  + "Synchronous DNS IPv6 localhost resolution failed. Please verify localhost resolves to ::1 "
  + "in /etc/hosts, since this misconfiguration is a common cause of these failures.";
  + EXPECT_EQ(nullptr, resolver_->resolve("localhost", DnsLookupFamily::V6Only,
  [&](std::list<Address::InstanceConstSharedPtr>&& results)
  - -> void { address_list = results; }));
  + -> void { address_list = results; }))
  + << error_msg;
  + EXPECT_TRUE(hasAddress(address_list, "::1")) << error_msg;
  EXPECT_FALSE(hasAddress(address_list, "127.0.0.1"));
  - EXPECT_TRUE(hasAddress(address_list, "::1"));
  - EXPECT_EQ(nullptr, resolver_->resolve("localhost", DnsLookupFamily::V6Only,
  + EXPECT_EQ(nullptr, resolver_->resolve("localhost", DnsLookupFamily::Auto,
  [&](std::list<Address::InstanceConstSharedPtr>&& results)
  - -> void { address_list = results; }));
  - EXPECT_TRUE(hasAddress(address_list, "::1"));
  + -> void { address_list = results; }))
  + << error_msg;
  EXPECT_FALSE(hasAddress(address_list, "127.0.0.1"));
  + EXPECT_TRUE(hasAddress(address_list, "::1")) << error_msg;
  }
  }
  