如何使用htaccess保护codeigniter安装的子目录?

我在根目录下安装了codeigniter,并希望使用htaccess来保护名为“test”的子目录。不管我怎么尝试,我总是得到一个“404页没有找到”。目录结构为:

/public_html  
    /css  
    /images
    /system (codeigniter directory)
    /test
        .htaccess
.htaccess
.htpasswd
index.php

根.htaccess文件如下:

RewriteEngine On
RewriteBase /

Options -Indexes    

# Removes trailing slashes
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)/$ $1 [L,R=301]

# Enforce www
RewriteCond %{HTTP_HOST} !^(www) [NC]
RewriteRule ^(.*)$ http://www.mydomain.com/$1 [L,R=301]


#Checks to see if the user is attempting to access a valid file,
#such as an image or css document, if this isn't true it sends the
#request to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !^(.*)test(.*)    
RewriteRule ^(.*)$ index.php?/$1 [L]

/test/.htaccess文件:

AuthUserFile /home/dir/.htpasswd
AuthName "Protected Area"
AuthType Basic
<limit GET POST PUT>
  require user adminuser
</limit>

我甚至没有得到身份验证提示,只有导航到url时的codeigniter 404页面。” http://www.mydomain.com/test/ “。

请告知!