net/ftp.rb: NullSocket#closed?

* net/ftp.rb: add NullSocket#closed? to fix closing not opened
  connection.  [Fix GH-1232]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53810 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Fri Feb 12 11:49:49 2016  Anthony Dmitriyev  <antstorm@gmail.com>
+
+	* net/ftp.rb: add NullSocket#closed? to fix closing not opened
+	  connection.  [Fix GH-1232]
+
 Fri Feb 12 11:17:38 2016  Bogdan  <bogdanvlviv@gmail.com>
 
 	* re.c (rb_reg_initialize_m): [DOC] fix missing right bracket.

lib/net/ftp.rb

@@ -1270,6 +1270,10 @@ module Net
       def read_timeout=(sec)
       end
 
+      def closed?
+        true
+      end
+
       def close
       end
 

test/net/ftp/test_ftp.rb

@@ -29,6 +29,14 @@ class FTPTest < Test::Unit::TestCase
     end
   end
 
+  def test_closed_when_not_connected
+    ftp = Net::FTP.new
+    assert_equal(true, ftp.closed?)
+    assert_nothing_raised(Net::FTPConnectionError) do
+      ftp.close
+    end
+  end
+
   def test_connect_fail
     server = create_ftp_server { |sock|
       sock.print("421 Service not available, closing control connection.\r\n")