Rails2から4へ移行を試みています。

ほぼ終わったのですが、認証をDeviseに変えたのが祟ったか
 test:integration で躓いています。
ご指導ください。
                                出沢

問題
  ユーザ認証が通りません。
  rails server を起動してブラウザでの認証は通ります。

1. devise.rbにて認証keyはusernameにしてあります。
     config.authentication_keys =  [:username]

2. ソース
===== test/integration/login_test.rb =====
# -*- coding: utf-8 -*-
require 'test_helper'

class LoginTest  < ActionDispatch::IntegrationTest

  fixtures :users
  test "Appを呼ぶと" do
    get "/app"
    assert_redirected_to "/users/sign_in","ログインを求められる"

    post user_session_path,username: "aaron",password: "aaronpass"
    assert_equal nil,flash[:alert]
    assert_equal "Signed in successfully.",flash[:notice]
  end


3. 結果
 rake test:integration
  1) Failure:
AppTest#test_Appを呼ぶと
[/home/dezawa/MSDN/msdn/test/integration/app_test.rb:12]:
Expected: nil
  Actual: "Invalid email or password."


  12行めは assert_equal nil,flash[:alert] の所です。

log/test.log
---------------------
AppTest: test_Appを呼ぶと
---------------------
Started GET "/app" for 127.0.0.1 at 2013-12-26 16:21:28 +0900
Processing by AppController#index as HTML
Completed 401 Unauthorized in 110ms
Started POST "/users/sign_in" for 127.0.0.1 at 2013-12-26 16:21:29 +0900
Processing by Devise::SessionsController#create as HTML
  Parameters: {"username"=>"aaron", "password"=>"[FILTERED]"}
Completed 401 Unauthorized in 1ms
Processing by Devise::SessionsController#new as HTML
  Parameters: {"username"=>"aaron", "password"=>"[FILTERED]"}
  Rendered devise/shared/_links.erb (2.0ms)
  Rendered devise/sessions/new.html.erb within layouts/application (93.8ms)
Completed 200 OK in 176ms (Views: 149.2ms | ActiveRecord: 0.0ms)

4. 環境
  Ubintu 13.10  on VMweare Player
  ruby 1.9.3p194 (2012-04-20 revision 35410) [i686-linux]
  Rails 4.0.1
  devise (3.2.1)

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