🧪 Add Net::IMAP::FakeServer::TestHelper

This simplifies using Net::IMAP::FakeServer in multiple test suites.

test/net/imap/fake_server.rb

@@ -42,6 +42,7 @@ class Net::IMAP::FakeServer
   autoload :ResponseWriter,        "#{dir}/response_writer"
   autoload :Socket,                "#{dir}/socket"
   autoload :Session,               "#{dir}/session"
+  autoload :TestHelper,            "#{dir}/test_helper"
 
   # Returns the server's FakeServer::Configuration
   attr_reader :config

test/net/imap/fake_server/test_helper.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require_relative "../fake_server"
+
+module Net::IMAP::FakeServer::TestHelper
+
+  def with_fake_server(select: nil, timeout: 5, **opts)
+    Timeout.timeout(timeout) do
+      server = Net::IMAP::FakeServer.new(timeout: timeout, **opts)
+      @threads << Thread.new do server.run end if @threads
+      tls = opts[:implicit_tls]
+      tls = {ca_file: server.config.tls[:ca_file]} if tls == true
+      client = Net::IMAP.new("localhost", port: server.port, ssl: tls)
+      begin
+        if select
+          client.select(select)
+          server.commands.pop
+        end
+        yield server, client
+      ensure
+        client.logout rescue pp $!
+        client.disconnect if !client.disconnected?
+      end
+    ensure
+      server&.shutdown
+    end
+  end
+
+end