TPT-4209: Integration tests for NB Front-End IP & 40Gbps

[mawilk90]

📝 Description

Integration tests for NodeBalancer Front-End IP in VPC and 40Gbps NodeBalancer-MTC

NOTES:
1. PR with openapi.json for NBs not merged yet so CLI should be build locally and this PR cannot be merged for now
2. Preferred env: Prod as there is no valid region on DevCloud to create nodebalancers of type=premium_40gb

✔️ How to Test

CLI build: SPEC=path/to/locally/stored/openapi.json make install

Tests: make test-int TEST_SUITE=nodebalancers TEST_ARGS="-k test_nb_with"

[Copilot]

Pull request overview

Adds new integration coverage for NodeBalancer VPC front-end IP behavior and the premium_40gb NodeBalancer type, including supporting test helpers/fixtures to provision a VPC+subnet in an eligible region.

Changes:

• Added NodeBalancer integration tests for backend VPC attachment, frontend VPC IPv4 assignment, expected failure cases, and premium_40gb creation.
• Added a NodeBalancer-local fixture to create/cleanup a VPC with a subnet for these tests.
• Extended region selection helpers to optionally restrict to a known-valid region allowlist (and updated VPC creation helper accordingly).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
tests/integration/nodebalancers/test_node_balancers.py	Adds premium region allowlists and new NB/VPC integration tests; adjusts a few UDP node output expectations.
tests/integration/nodebalancers/conftest.py	Adds get_vpc_with_subnet fixture for NB tests, using shared VPC creation helper.
tests/integration/helpers.py	Extends get_random_region_with_caps with valid_regions filtering.
tests/integration/conftest.py	Updates create_vpc_w_subnet to accept valid_regions and selects regions with both VPC and NodeBalancer capabilities.

Comments suppressed due to low confidence (1)

tests/integration/conftest.py:234

• get_random_region_with_caps(...) can return None (e.g., when valid_regions filters out all matches), but create_vpc_w_subnet passes region straight into the CLI args. Add an explicit check after region selection (e.g., assert/skip with a clear message) to avoid hard-to-debug failures like --region None when no eligible region is available.

    region = get_random_region_with_caps(
        required_capabilities=["VPCs", "NodeBalancers"],
        valid_regions=valid_regions,
    )
    vpc_label = get_random_text(5) + "label"
    subnet_label = get_random_text(5) + "label"

    vpc_json = json.loads(
        exec_test_command(
            [
                "linode-cli",
                "vpcs",
                "create",
                "--label",
                vpc_label,
                "--region",
                region,
                # "--ipv6.range",    TODO: Uncomment after VPC Dual Stack is ready to ship

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[dawiddzhafarov]

Do we want to point this branch to proj branch, to keep it consistent and not merge it accidentally to the dev branch without released openapi.json?

[mawilk90]

@dawiddzhafarov

Do we want to point this branch to proj branch, to keep it consistent and not merge it accidentally to the dev branch without released openapi.json?

Generally I haven't seen any proj branch here and previously integration tests have been megred directly into dev (example: #801) so I decided to follow the same path