test: implemented the interop test with rust libp2p

[ItshMoh]

summary

fixes #1142

Implements interoperability tests between py-libp2p and rust-libp2p using the /ipfs/ping/1.0.0 protocol over TCP transport.

What's Included

New Files

• tests/interop/rust_libp2p/test_ping_interop.py- Python test that connects to a Rust ping server and validates RTT responses
• tests/interop/rust_libp2p/conftest.py- Pytest fixtures for building and managing the Rust server lifecycle
• tests/interop/rust_libp2p/rust_node/ - Rust ping server implementation using rust-libp2p
• tests/interop/rust_libp2p/README.md - Documentation with prerequisites and instructions

Test Coverage

The test verifies:

• TCP Transport Compatibility: Connection establishment between py-libp2p and rust-libp2p
• Multistream Protocol Negotiation: /ipfs/ping/1.0.0 selected via multistream-select
• Pings: Sends 5 pings and validates positive RTT values are returned

How to Run

cd tests/interop/rust_libp2p
pytest -v -s --log-cli-level=INFO

Cute Animal Picture

[seetadev]

@ItshMoh : Hi Mohan. Thanks for taking this on — this is a much-needed gap to fill, and the proposal looks solid 👍
Rust ↔ Python interop using Ping is a good starting point, and following the nim-libp2p interop structure is the right reference.

A few important pointers to help you align this correctly, especially since you’re new to the libp2p codebase:

📍 Where interop tests should live

Even though there’s a placeholder under py-libp2p/tests/interop/rust_libp2p, new interoperability tests should be implemented in:
👉 https://github.com/libp2p/test-plans

That repo is the canonical home for:

• Cross-implementation interop tests (rust ↔ python, js ↔ python, etc.)
• Shared orchestration logic
• Long-term interop coverage tracked across stacks

Please follow the structure and conventions documented here:
https://github.com/libp2p/test-plans/tree/master/docs

📦 py-libp2p PR scope

PRs to py-libp2p → main should only be opened if:

• You’re modifying core library behavior, or
• You’re changing/adding shared utilities used by py-libp2p itself

Test plans and cross-stack validation logic should stay out of the core repo and live in test-plans.

🧭 On the approach

• Using Ping for Rust ↔ Python interop is reasonable.
• If, while implementing this, you discover a missing primitive or a bug in py-libp2p, then a focused PR to py-libp2p is totally appropriate.

🤝 Maintainers sync (important for new contributors)

Since you’re a new contributor, please try to join the libp2p maintainers meeting every Thursday.
It’s the fastest way to:

• Validate interop test scope
• Align with ongoing Rust / Go / JS interop work
• Avoid duplicating effort and get quick feedback

Overall, this is a strong and well-motivated contribution. Once this is set up in test-plans following the docs, happy to review and help iterate. Keep going 🚀

CCing @sumanjeet0012 , @acul71 and @dhuseby