Index: lib/net/smtp.rb
===================================================================
--- lib/net/smtp.rb	(revision 35583)
+++ lib/net/smtp.rb	(working copy)
@@ -817,6 +817,10 @@ module Net
 
     public
 
+    def rset
+      getok('RSET')
+    end
+
     def starttls
       getok('STARTTLS')
     end
Index: test/net/smtp/test_smtp.rb
===================================================================
--- test/net/smtp/test_smtp.rb	(revision 35583)
+++ test/net/smtp/test_smtp.rb	(working copy)
@@ -1,8 +1,26 @@
 require 'net/smtp'
+require 'stringio'
 require 'minitest/autorun'
 
 module Net
   class TestSMTP < MiniTest::Unit::TestCase
+    class FakeSocket
+      def initialize out = "250 OK\n"
+        @write_io = StringIO.new
+        @read_io  = StringIO.new out
+      end
+
+      def writeline line
+        @write_io.write "#{line}\r\n"
+      end
+
+      def readline
+        line = @read_io.gets
+        raise 'ran out of input' unless line
+        line.chop
+      end
+    end
+
     def test_esmtp
       smtp = Net::SMTP.new 'localhost', 25
       assert smtp.esmtp
@@ -12,5 +30,12 @@ module Net
       assert_equal 'omg', smtp.esmtp
       assert_equal 'omg', smtp.esmtp?
     end
+
+    def test_rset
+      smtp = Net::SMTP.new 'localhost', 25
+      smtp.instance_variable_set :@socket, FakeSocket.new
+
+      assert smtp.rset
+    end
   end
 end