trying to check whether fail at first or not

test/test_a.rb

@@ -0,0 +1,68 @@
+require_relative '../helper'
+require 'fluent/plugin_helper/server'
+require 'fluent/plugin/base'
+require 'timeout'
+
+require 'serverengine'
+require 'fileutils'
+
+class AToFailAtFirstTest < Test::Unit::TestCase
+  class Dummy < Fluent::Plugin::TestBase
+    helpers :server
+  end
+
+  PORT = unused_port
+
+  setup do
+    @socket_manager_path = ServerEngine::SocketManager::Server.generate_path
+    if @socket_manager_path.is_a?(String) && File.exist?(@socket_manager_path)
+      FileUtils.rm_f @socket_manager_path
+    end
+    @socket_manager_server = ServerEngine::SocketManager::Server.open(@socket_manager_path)
+    ENV['SERVERENGINE_SOCKETMANAGER_PATH'] = @socket_manager_path.to_s
+
+    @d = Dummy.new
+    @d.start
+    @d.after_start
+  end
+
+  teardown do
+    @d.stopped? || @d.stop
+    @d.before_shutdown? || @d.before_shutdown
+    @d.shutdown? || @d.shutdown
+    @d.after_shutdown? || @d.after_shutdown
+    @d.closed? || @d.close
+    @d.terminated? || @d.terminate
+
+    @socket_manager_server.close
+    if @socket_manager_server.is_a?(String) && File.exist?(@socket_manager_path)
+      FileUtils.rm_f @socket_manager_path
+    end
+  end
+
+  sub_test_case '#server_create and #server_create_connection' do
+    data(
+      'server_create tcp' => [:server_create, :tcp, {}],
+      'server_create udp' => [:server_create, :udp, {max_bytes: 128}],
+      # 'server_create tls' => [:server_create, :tls, {}],
+      # 'server_create unix' => [:server_create, :unix, {}],
+      'server_create_connection tcp' => [:server_create, :tcp, {}],
+      # 'server_create_connection tls' => [:server_create, :tls, {}],
+      # 'server_create_connection unix' => [:server_create, :unix, {}],
+    )
+    test 'cannot create 2 or more servers using same bind address and port if shared option is false' do |(m, proto, kwargs)|
+      begin
+        d2 = Dummy.new; d2.start; d2.after_start
+
+        assert_nothing_raised do
+          @d.__send__(m, :myserver, PORT, proto: proto, shared: false, **kwargs){|x| x }
+        end
+        assert_raise(Errno::EADDRINUSE) do
+          d2.__send__(m, :myserver, PORT, proto: proto, **kwargs){|x| x }
+        end
+      ensure
+        d2.stop; d2.before_shutdown; d2.shutdown; d2.after_shutdown; d2.close; d2.terminate
+      end
+    end
+  end
+end