Comment 3 for bug 1602066

I added the HWE support information to update-manager for Trusty (bug 1498059) so can provide you with information as to what a manual test case would involve. I've just approved (literally minutes ago) a new version of update-manager in trusty-proposed which fixes a couple of strings namely recommending to upgrade from 12.04 to 14.04.

There are two parts to the HWE support in update-manager. One is the tool hwe-support-status which provides information about the support for your HWE stack. After 8/4/2016, when support ends for the U,V,W HWE stacks, it will provide information about how to upgrade. Some tests for hwe-support-status would include:

Run hwe-support-status and observe it security updates are no longer available for your HWE stack.
  * If update-manager is installed it will recommend upgrading via update-manager.
  * If update-manager is not installed it will provide a list of packages to upgrade via apt-get.

Running hwe-support-status with --show-replacements should list packages from the next LTS e.g. xenial.

Running hwe-support-status with --show-unsupported should list your current HWE stack packages e.g. with lts-vivid in them.

Running hwe-support-status --quiet should exit with code 10.