slices,tests: add dhcpcd-base

[Meulengracht]

Proposed changes

dhcpcd-base is required for Ubuntu Core 26

Checklist

• I have read the contributing guidelines
• I have tested my changes (see how)
• I have already submitted the CLA form

[lczyk]

• blocked on ci error preparing lxd machine in test #828. working on a fix. for now cancelled the integration tests as they would never succeed and eventually time out, and they were taking up worker allocation. will re-trigger when ci is back to a working state. apologies for the inconvenience!

[lczyk]

• ci error preparing lxd machine in test #828 resolved. removing 'blocked' and updating with the base branch

[alesancor1]

Slices LGTM, I have some comments on testing: Check below:

[alesancor1]

It's included already by dhcpcd-base_hooks-standard and dhcpcd-base_core so no need to have it here:

Suggested change

- dhcpcd-base_hooks-core

[alesancor1]

You need to use a different approach here, since spread will run the tests with set -e, meaning some of the if statements will cause a failure.

[alesancor1]

What about standard? We should test it, too. Feel free to use this approach

[alesancor1]

You are only testing the existence of certain files here (appart from the -h flag). Can we add some functionality testing? Maybe a bit complex, but you can try to:

1. Create a test network namespace:

ip netns add dhcp-test

2. Attatch a virtual eth cable (veth pair):

ip link add veth0 type veth peer name veth1
ip link set veth1 netns dhcp-test

3. Configure the host side:

ip addr add 10.0.0.1/24 dev veth0
ip link set veth0 up

4. Start a test(fake) DHCP:

dnsmasq \
  --interface=veth0 \
  --bind-interfaces \
  --dhcp-range=10.0.0.50,10.0.0.60,12h

5. Bring the setup to life

ip netns exec dhcp-test ip link set lo up
ip netns exec dhcp-test ip link set veth1 up

6. Run dhcpcd and check an IP was assigned

ip netns exec dhcp-test chroot dhcpcd -d veth1
ip netns exec dhcp-test ip -4 addr show veth1 | grep -q "inet "

Then clean up everything with something like:

pkill dnsmasq 2>/dev/null || true
ip link del veth0 2>/dev/null || true
ip netns del dhcp-test 2>/dev/null || true