Fix flaky web push test and deduplicate DNS stub helper (#2825)

* Extract shared DnsTestHelper from duplicated stub_dns_resolution methods

* Fix flaky WebTest by stubbing DNS resolution for push subscription creation

test/controllers/api/flat_json_params_test.rb

@@ -247,11 +247,4 @@ class FlatJsonParamsTest < ActionDispatch::IntegrationTest
     assert_response :no_content
     assert_equal "Flat Join", users(:david).reload.name
   end
-
-  private
-    def stub_dns_resolution(*ips)
-      dns_mock = mock("dns")
-      dns_mock.stubs(:each_address).multiple_yields(*ips)
-      Resolv::DNS.stubs(:open).yields(dns_mock)
-    end
 end

test/controllers/users/push_subscriptions_controller_test.rb

@@ -92,11 +92,4 @@ class Users::PushSubscriptionsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_entity
   end
-
-  private
-    def stub_dns_resolution(*ips)
-      dns_mock = mock("dns")
-      dns_mock.stubs(:each_address).multiple_yields(*ips)
-      Resolv::DNS.stubs(:open).yields(dns_mock)
-    end
 end

test/models/notification/push_target/web_test.rb

@@ -5,6 +5,8 @@ class Notification::PushTarget::WebTest < ActiveSupport::TestCase
     @user = users(:david)
     @notification = notifications(:logo_mentioned_david)
 
+    stub_dns_resolution("142.250.185.206")
+
     @user.push_subscriptions.create!(
       endpoint: "https://fcm.googleapis.com/fcm/send/test123",
       p256dh_key: "test_key",

test/models/push/subscription_test.rb

@@ -115,11 +115,4 @@ class Push::SubscriptionTest < ActiveSupport::TestCase
       assert subscription.valid?, "Expected #{endpoint} to be valid, got errors: #{subscription.errors.full_messages}"
     end
   end
-
-  private
-    def stub_dns_resolution(*ips)
-      dns_mock = mock("dns")
-      dns_mock.stubs(:each_address).multiple_yields(*ips)
-      Resolv::DNS.stubs(:open).yields(dns_mock)
-    end
 end

test/models/ssrf_protection_test.rb

@@ -82,11 +82,4 @@ class SsrfProtectionTest < ActiveSupport::TestCase
     stub_dns_resolution("::93.184.216.34")
     assert_nil SsrfProtection.resolve_public_ip("compat-public.example.com")
   end
-
-  private
-    def stub_dns_resolution(*ips)
-      dns_mock = mock("dns")
-      dns_mock.stubs(:each_address).multiple_yields(*ips)
-      Resolv::DNS.stubs(:open).yields(dns_mock)
-    end
 end

test/models/webhook/delivery_test.rb

@@ -473,11 +473,4 @@ class Webhook::DeliveryTest < ActiveSupport::TestCase
     assert_equal 200, delivery.response[:code]
     assert delivery.succeeded?
   end
-
-  private
-    def stub_dns_resolution(*ips)
-      dns_mock = mock("dns")
-      dns_mock.stubs(:each_address).multiple_yields(*ips)
-      Resolv::DNS.stubs(:open).yields(dns_mock)
-    end
 end

test/test_helper.rb

@@ -45,7 +45,7 @@ module ActiveSupport
     fixtures :all
 
     include ActiveJob::TestHelper
-    include ActionTextTestHelper, CachingTestHelper, CardTestHelper, ChangeTestHelper, SessionTestHelper
+    include ActionTextTestHelper, CachingTestHelper, CardTestHelper, ChangeTestHelper, DnsTestHelper, SessionTestHelper
     include Turbo::Broadcastable::TestHelper
 
     # Jobs must carry their own account context via AccountTenanted,

test/test_helpers/dns_test_helper.rb

@@ -0,0 +1,9 @@
+module DnsTestHelper
+  private
+
+  def stub_dns_resolution(*ips)
+    dns_mock = mock("dns")
+    dns_mock.stubs(:each_address).multiple_yields(*ips)
+    Resolv::DNS.stubs(:open).yields(dns_mock)
+  end
+end