XCPNG-3592: network: VLAN filtering tests

[semarie]

add basic tests on VLAN filtering.

• configure a trunk over internal network to avoid CI conflicts
• start 1 VM using the trunk and monitoring packets
• start 1 VM sending packets on specific VLAN
• ensure trunks parameter (on first VM) properly let's pass or filter the VLAN

[semarie]

Keep the PR as draft while xapi package with VLAN filtering isn't published

[bleader]

The test file is named test_trunks, tests themselves are test_passing and test_filtered, it is not super obvious that we are testing filtering beside the test_filtered, I would like to make it more obvious. Either we dedicate the file itself to filtering and rename it, or we want to add mapping or more generic trunking tests in the future to it, and in that case the tests name can be changed. What do you think?

[semarie]

naming is complex 😄

the test file is named test_trunks because it is about testing the trunks attribute on VIF (used for VLAN filtering), named itself from the trunks attribute in OVS (which is used to configure which VLAN are allowed on the VIF).

But I agree it could be misleading. I will rename the file.

[semarie]

Last push:

• rename test_trunks.py to test_vlan_filtering.py
• add a Requirements comment at top of file

[semarie]

Making ready for review as the feature has been published in 8.3-20260818

[semarie]

Last push:

• rebase on top of master
• incoporate feedback from @glehmann