TestOVNMechanismDriver some ipv6 tests fails if host has ipv6 dns_names configured

[Arnau Verdaguer]

If host where tests are executed has ipv6 dns_servers configured on /etc/resolv.conf two test fails.
The tests are:
- neutron.tests.unit.plugins.ml2.drivers.ovn.mech_driver.test_mech_driver.TestOVNMechanismDriver.test_update_subnet_dhcp_options_in_ovn_ipv6_not_change
- neutron.tests.unit.plugins.ml2.drivers.ovn.mech_driver.test_mech_driver.TestOVNMechanismDriver.test_enable_subnet_dhcp_options_in_ovn_ipv6

This is due to not patching the ovn_utils.get_system_dns_resolvers which ends up looking at host for dns_servers.
This doesn't happen on ipv4 since on the setup the ipv4 dns_servers are set using ovn_conf.cfg.CONF.set_override.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/912475

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/912475
Committed: https://opendev.org/openstack/neutron/commit/2a196fefd4a8a0c15176fe87d88b05d1690ab5fa
Submitter: "Zuul (22348)"
Branch: master

commit 2a196fefd4a8a0c15176fe87d88b05d1690ab5fa
Author: Arnau Verdaguer <email address hidden>
Date: Mon Mar 11 17:30:11 2024 +0100

    Fix TestOVNMechanismDriver ipv6 tests

    - test_update_subnet_dhcp_options_in_ovn_ipv6_not_change
    - test_enable_subnet_dhcp_options_in_ovn_ipv6
    This tests will fail if host where unit tests has ipv6 dns_servers
    configured. This patch mocks get_system_dns_servers to avoid tests
    to look at the host configuration.

    Closes-Bug: #2056778
    Change-Id: I2e703ab4b63c90d7a14f0dc41d37b0a98163bce0

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/2023.2
Review: https://review.opendev.org/c/openstack/neutron/+/912072

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/2023.1
Review: https://review.opendev.org/c/openstack/neutron/+/912073

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/912072
Committed: https://opendev.org/openstack/neutron/commit/8db03d65e851033d3830a6b502c839c03111f16d
Submitter: "Zuul (22348)"
Branch: stable/2023.2

commit 8db03d65e851033d3830a6b502c839c03111f16d
Author: Arnau Verdaguer <email address hidden>
Date: Mon Mar 11 17:30:11 2024 +0100

    Fix TestOVNMechanismDriver ipv6 tests

    - test_update_subnet_dhcp_options_in_ovn_ipv6_not_change
    - test_enable_subnet_dhcp_options_in_ovn_ipv6
    This tests will fail if host where unit tests has ipv6 dns_servers
    configured. This patch mocks get_system_dns_servers to avoid tests
    to look at the host configuration.

    Closes-Bug: #2056778
    Change-Id: I2e703ab4b63c90d7a14f0dc41d37b0a98163bce0
    (cherry picked from commit 2a196fefd4a8a0c15176fe87d88b05d1690ab5fa)

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/912073
Committed: https://opendev.org/openstack/neutron/commit/a8bf8cdaa6d80d77d80b3af3a8dad18178f6fb76
Submitter: "Zuul (22348)"
Branch: stable/2023.1

commit a8bf8cdaa6d80d77d80b3af3a8dad18178f6fb76
Author: Arnau Verdaguer <email address hidden>
Date: Mon Mar 11 17:30:11 2024 +0100

    Fix TestOVNMechanismDriver ipv6 tests

    - test_update_subnet_dhcp_options_in_ovn_ipv6_not_change
    - test_enable_subnet_dhcp_options_in_ovn_ipv6
    This tests will fail if host where unit tests has ipv6 dns_servers
    configured. This patch mocks get_system_dns_servers to avoid tests
    to look at the host configuration.

    Closes-Bug: #2056778
    Change-Id: I2e703ab4b63c90d7a14f0dc41d37b0a98163bce0
    (cherry picked from commit 2a196fefd4a8a0c15176fe87d88b05d1690ab5fa)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 24.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/zed
Review: https://review.opendev.org/c/openstack/neutron/+/915523

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/915523
Committed: https://opendev.org/openstack/neutron/commit/de9e3e8c9bb78feb71c47f886f8d785f55568b6d
Submitter: "Zuul (22348)"
Branch: stable/zed

commit de9e3e8c9bb78feb71c47f886f8d785f55568b6d
Author: Arnau Verdaguer <email address hidden>
Date: Mon Mar 11 17:30:11 2024 +0100

    Fix TestOVNMechanismDriver ipv6 tests

    - test_update_subnet_dhcp_options_in_ovn_ipv6_not_change
    - test_enable_subnet_dhcp_options_in_ovn_ipv6
    This tests will fail if host where unit tests has ipv6 dns_servers
    configured. This patch mocks get_system_dns_servers to avoid tests
    to look at the host configuration.

    Closes-Bug: #2056778
    Change-Id: I2e703ab4b63c90d7a14f0dc41d37b0a98163bce0
    (cherry picked from commit 2a196fefd4a8a0c15176fe87d88b05d1690ab5fa)
    (cherry picked from commit a8bf8cdaa6d80d77d80b3af3a8dad18178f6fb76)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 21.2.1 release.