Comment 12 for bug 2038958

In testing this for Mantic, I realized something important: we can't actually test it quite yet, because Noble hasn't been released! If we modified the package further, that will require another round of SRU + testing.

I asked myself, how exactly does do-release-upgrade get this information? Well, it gets it from https://changelogs.ubuntu.com/meta-release (when set to "normal," of course.) If I could simply MITM changelogs.ubuntu.com in my sandbox environment, that will simulate Noble being released. Unlike plasma-distro-release-notifier, our notifier system doesn't care about ubuntu.csv. It'll notify whenever the release is ready. This is the only way I can possibly see to test this without actually changing the package in any way, or adding UX for devel upgrades, which is outside the scope of this SRU entirely.

Here's my MITMProxy script (consider it as DWTFYW-licensed):
# cat test.py
class AddHeader:
    def response(self, flow):
        replacement_content = ""
        with open("/tmp/meta-release", "r") as file:
            replacement_content = file.read()
        flow.response.text = replacement_content

addons = [
    AddHeader()
]

This successfully tricked do-release-upgrade into thinking there's a new release available, which therefore triggered this upgrade.

In terms of lubuntu-update-notifier, which is what we're specifically testing for, verification is successful, with version 0.6.2~23.10.1 in mantic-proposed. I followed the same instructions as Lunar, precisely.