Here are the two test cases I've run for this SRU:


Test 1
======

Enable dapper-proposed and dist-upgrade. 
Install update-manager-core, apache2.

Enable proxy module:
  sudo a2enmod proxy

Do release upgrade:
  do-release-upgrade -d

Check that the disk_cache module is not enabled after the upgrade (and that proxy_http is):
 * Upgrade logs:
Module alias installed; run /etc/init.d/apache2 force-reload to enable.
Module autoindex installed; run /etc/init.d/apache2 force-reload to enable.
Module dir installed; run /etc/init.d/apache2 force-reload to enable.
Module env installed; run /etc/init.d/apache2 force-reload to enable.
Module mime installed; run /etc/init.d/apache2 force-reload to enable.
Module negotiation installed; run /etc/init.d/apache2 force-reload to enable.
Module setenvif installed; run /etc/init.d/apache2 force-reload to enable.
Module status installed; run /etc/init.d/apache2 force-reload to enable.
Module auth_basic installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_default installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_user installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_groupfile installed; run /etc/init.d/apache2 force-reload to enable.
Module authn_file installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_host installed; run /etc/init.d/apache2 force-reload to enable.
Enabling proxy as a dependency
This module is already enabled!
Module proxy_http installed; run /etc/init.d/apache2 force-reload to enable.

 * $ ls /etc/apache2/mods-enabled/*cache*
   ls: cannot access /etc/apache2/mods-enabled/*cache*: No such file or directory

 * $ ls /etc/apache2/mods-enabled/*proxy_http*
   /etc/apache2/mods-enabled/proxy_http.load
 
Test 2
======

Enable dapper-proposed and dist-upgrade. 
Install update-manager-core, apache2.

Enable proxy module:
  sudo a2enmod proxy

Enable disk caching for the root url:
 * edit /etc/apache2/sites-enabled/000-default 
   to add "CacheEnable disk /" to the VirtualHost section:

  <VirtualHost *>
    [...]

+    CacheEnable disk /

  </VirtualHost>

Check that caching works:
 * Load the index.html page from the web server in a browser.
 * $ ls /var/cache/apache2/proxy/
   0g  E3  jM

Delete cache:
 rm -rf /var/cache/apache2/proxy/*

Do release upgrade:
  do-release-upgrade -d

Check that disk_cache and proxy_http modules are enabled after the upgrade:
 * Upgrade logs:
Module alias installed; run /etc/init.d/apache2 force-reload to enable.
Module autoindex installed; run /etc/init.d/apache2 force-reload to enable.
Module dir installed; run /etc/init.d/apache2 force-reload to enable.
Module env installed; run /etc/init.d/apache2 force-reload to enable.
Module mime installed; run /etc/init.d/apache2 force-reload to enable.
Module negotiation installed; run /etc/init.d/apache2 force-reload to enable.
Module setenvif installed; run /etc/init.d/apache2 force-reload to enable.
Module status installed; run /etc/init.d/apache2 force-reload to enable.
Module auth_basic installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_default installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_user installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_groupfile installed; run /etc/init.d/apache2 force-reload to enable.
Module authn_file installed; run /etc/init.d/apache2 force-reload to enable.
Module authz_host installed; run /etc/init.d/apache2 force-reload to enable.
Enabling proxy as a dependency
This module is already enabled!
Module proxy_http installed; run /etc/init.d/apache2 force-reload to enable.
Enabling cache as a dependency
Module cache installed; run /etc/init.d/apache2 force-reload to enable.
Module disk_cache installed; run /etc/init.d/apache2 force-reload to enable.

 * $ ls /etc/apache2/mods-enabled/*cache*
   /etc/apache2/mods-enabled/cache.load
   /etc/apache2/mods-enabled/disk_cache.conf
   /etc/apache2/mods-enabled/disk_cache.load
 
 * $ ls /etc/apache2/mods-enabled/*proxy_http*
   /etc/apache2/mods-enabled/proxy_http.load

Check that caching works:
 * Load the index.html page from the server.
 * List the content of the caching directory:
   $ ls /var/cache/apache2/mod_disk_cache/
   ZfO
 * Check that htcacheclean is started:
   $ pgrep htcacheclean
   4912