server.rb

  def start( port = 24842 )
    server = TCPServer.new( port )
    log "[server log] Server started on localhost: #{port}"

    while @session = server.accept
    
      # 1) get the username
      username = @session.gets.chomp
      log "[server log] Received Client's Username: #{username}"
      
      # 2) send the salt
      salt = generate_salt
      @session.puts(salt)
      log "[server log] Sent Client Salt: #{salt}"
      log "[server log] Awaiting Client's Salted Password..."
      
      # 3) get auth string  
      client_salted_pwd = @session.gets.chomp
      log "[server log] Received Salted Password: #{client_salted_pwd}"
      
      # 4) Check Auth String & Return Results
      if authenticated( username, salt, client_salted_pwd )
        @session.puts("AUTHORIZED")
        log "[server log] SUCCESSFUL Authentication for Username: #{username}"
      else
        @session.puts( "NOT AUTHORIZED" )
        log "[server log] FAILED Authentication for Username: #{username}"
      end
      log "[server log] Closing Session..."
      
      # 5) Disconnect Session
      @session.close
    end
  end

test_server.rb

class TestServer < Test::Unit::TestCase

  KNOWN_CREDS = { "alice" => "foo" }

  def setup
    YAML.expects( :load_file ).with( 'passwd' ).returns( KNOWN_CREDS )
    @server     = Server.new
    @tcp_server = mock( 'fake_tcp' )
    @session    = mock( 'session' )
    @salt       = "salt"
    @user       = "user"
    @salt_pass  = "pass"
    @while_loop = sequence('while_loop')
  end

  def test_valid_user
    @tcp_server.expects( :accept ).returns( @session ).in_sequence( @while_loop )
    @tcp_server.expects( :accept ).returns( false    ).in_sequence( @while_loop )
    
    @session.expects( :gets          ).returns( @user         )
    @server.expects(  :generate_salt ).returns( @salt         )
    @session.expects( :puts          ).with(    @salt         )
    @session.expects( :gets          ).returns( @salt_pass    )

    ###
    # Should I be testing passing @username, @salt, @salt_pass here?
    ###

    @server.expects(  :authenticated ).returns( true          )
    @session.expects( :puts          ).with(    "AUTHORIZED"  )
    @session.expects( :close         )
    
    TCPServer.expects( :new ).returns( @tcp_server )
    
    @server.start
  end

end