From aecb68b6a8ad40dfaa3d2f5a6476cbe93d6a66bd Mon Sep 17 00:00:00 2001
From: Diogo Vernier <10981831+diogovernier@users.noreply.github.com>
Date: Thu, 9 Apr 2026 10:03:48 -0300
Subject: [PATCH] Use dynamic port allocation in Puma plugin tests

The Puma plugin tests bind to a hardcoded port (9222). When a test
teardown completes and the next test setup starts, the OS may still
hold the port in TCP TIME_WAIT state, causing EADDRINUSE failures
that cascade into nil process lookups and false test failures.

Replace the hardcoded port with a dynamically allocated one via
TCPServer, so each test gets a guaranteed available port.
---
 test/integration/puma/plugin_testing.rb | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/test/integration/puma/plugin_testing.rb b/test/integration/puma/plugin_testing.rb
index 14165c9b8..ccabd231b 100644
--- a/test/integration/puma/plugin_testing.rb
+++ b/test/integration/puma/plugin_testing.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "test_helper"
+require "socket"
 
 module PluginTesting
   extend ActiveSupport::Concern
@@ -12,10 +13,12 @@ module PluginTesting
     setup do
       FileUtils.mkdir_p Rails.root.join("tmp", "pids")
 
+      @port = find_available_port
+
       Dir.chdir("test/dummy") do
         cmd = %W[
           bundle exec puma
-            -b tcp://127.0.0.1:9222
+            -b tcp://127.0.0.1:#{@port}
             -C config/puma_#{solid_queue_mode}.rb
             -s
             config.ru
@@ -57,4 +60,11 @@ module PluginTesting
     def solid_queue_mode
       raise NotImplementedError
     end
+
+    def find_available_port
+      server = TCPServer.new("127.0.0.1", 0)
+      server.addr[1]
+    ensure
+      server&.close
+    end
 end