Stub DNS to return IPv4 address

Otherwise certain machines return IPv6 first, which is non-deterministic

spec/lib/gitlab/http_connection_adapter_spec.rb

@@ -3,7 +3,13 @@
 require 'spec_helper'
 
 describe Gitlab::HTTPConnectionAdapter do
+  include StubRequests
+
   describe '#connection' do
+    before do
+      stub_all_dns('https://example.org', ip_address: '93.184.216.34')
+    end
+
     context 'when local requests are not allowed' do
       it 'sets up the connection' do
         uri = URI('https://example.org')

spec/support/helpers/stub_requests.rb

@@ -28,6 +28,19 @@ module StubRequests
                          .and_return([addr])
   end
 
+  def stub_all_dns(url, ip_address:)
+    url = URI(url)
+    port = 80 # arbitarily chosen, does not matter as we are not going to connect
+    socket = Socket.sockaddr_in(port, ip_address)
+    addr = Addrinfo.new(socket)
+
+    # See Gitlab::UrlBlocker
+    allow(Addrinfo).to receive(:getaddrinfo).and_call_original
+    allow(Addrinfo).to receive(:getaddrinfo)
+      .with(url.hostname, anything, nil, :STREAM)
+      .and_return([addr])
+  end
+
   def stubbed_hostname(url, hostname: IP_ADDRESS_STUB)
     url = parse_url(url)
     url.hostname = hostname