test: add Ginkgo-based integration test framework for vpp-manager component

[aritrbas]

Summary

This PR introduces Ginkgo based tests for vpp-manager component.

Architecture

┌────────────────────────────────────────────────────────────────────┐
│                     Host Machine                                   │
│                                                                    │
│   ┌─────────────────────────────────────────────────────────────┐  │
│   │              Test Process (go test)                         │  │
│   │                                                             │  │
│   │  ┌─────────────────┐    ┌────────────────────────────────┐  │  │
│   │  │  VppFixture     │    │  vpp_manager_test.go           │  │  │
│   │  │ (pkg/testutils) │    │                                │  │  │
│   │  │                 │    │  - Creates VppRunner           │  │  │
│   │  │  - Start VPP    │    │  - Calls vpp_runner.go methods │  │  │
│   │  │  - Connect API  │    │  - Verifies VPP state          │  │  │
│   │  └────────┬────────┘    └────────────────────────────────┘  │  │
│   │           │                                                 │  │
│   └───────────┼─────────────────────────────────────────────────┘  │
│               │                                                    │
│               ▼                                                    │
│   ┌─────────────────────────────────────────────────────────────┐  │
│   │              Docker Container (VPP)                         │  │
│   │                                                             │  │
│   │  ┌───────────────────────────────────────────────────────┐  │  │
│   │  │                VPP Process                            │  │  │
│   │  │                                                       │  │  │
│   │  │  - API socket: /var/run/vpp/vpp-api-test.sock         │  │  │
│   │  │  - CLI socket: /var/run/vpp/cli.sock                  │  │  │
│   │  │                                                       │  │  │
│   │  └───────────────────────────────────────────────────────┘  │  │
│   │                                                             │  │
│   │  Volume Mount: /tmp/vpp-test-<name>/:/var/run/vpp/          │  │
│   │                                                             │  │
│   └─────────────────────────────────────────────────────────────┘  │
│                                                                    │
└────────────────────────────────────────────────────────────────────┘

Environment Variables

Variable	Default	Description
VPP_IMAGE	(required)	Docker image containing VPP
VPP_BINARY	/usr/bin/vpp	Path to VPP binary inside container

Test Structure

vpp-manager/
└── vpp_manager_test.go     # Tests

pkg/testutils/
├── vpp_instance.go         # VPP container management
├── fixtures.go             # Ginkgo fixtures
├── assertions.go           # VPP state assertions
└── helpers.go              # Helper functions

Test Coverage

Test	Description
VppRunner.allocateStaticVRFs	Verifies punt-table and calico-pods VRFs are created for IPv4/IPv6
VppRunner.AllocatePhysicalNetworkVRFs	Verifies physical network VRF allocation and config.Info registration
VPP Configuration	Verifies buffer allocation and plugin configuration in VPP
uplink Interface	Tests uplink interface addresses and VRFs configuration
TAP Interface	Tests TAP interface creation
AF_PACKET Interface	Tests AF_PACKET interface creation on veth pairs
memif Interface	Tests memif interface creation

Running Tests

make test

The tests are integrated into the main make test target:

# Build VPP image and run all tests
make test

# The test command includes these settings:
# sudo -E env "PATH=$$PATH" VPP_BINARY=/usr/bin/vpp \
#     VPP_IMAGE=calicovpp/vpp:$(TAG) \
#     go test ./... \
#     -cover -covermode=atomic -p 1 -test.v \
#     -test.gocoverdir=$(shell pwd)/.coverage/unit

go test

# Set environment variables
export VPP_IMAGE=calicovpp/vpp:latest
export VPP_BINARY=/usr/bin/vpp

# Run vpp-manager tests only
sudo -E go test -v ./vpp-manager/...

# Run with verbose Ginkgo output
sudo -E go test -v -ginkgo.v ./vpp-manager/...

# Run specific test by focus
sudo -E go test -v -ginkgo.focus="allocateStaticVRFs" ./vpp-manager/...

[sknat]

Thanks for taking a stab at it @aritrbas !
A few comments on the structure. Tell me if you want to discuss it in more details

[sknat]

Maybe we could call vpp_runner.go:configureVppUplinkInterface() directly instead of having a custom logic for tests

[aritrbas]

Ran into some issues while trying to test VppRunner.configureVppUplinkInterface() directly.
It creates a TAP with HostNamespace:"pid:1" that requires access to the host's PID 1 network namespace. In a Docker container, pid:1 refers to the container's init process, not the host, causing the Linux-side tap setup to fail.

For now, I have added a very basic uplink interface test that only verifies the VPP-side operations performed in configureVppUplinkInterface() - (i) VRF allocation (via allocateStaticVRFs()) (ii) Interface address configuration (via AddInterfaceAddress()) (iii) Interface state management (via InterfaceAdminUp())

Need to discuss how we can test the entire VppRunner.configureVppUplinkInterface() functionality using this framework, maybe handle it as a part of a separate task/PR?