Implemented: Envelope wrapper class + linter hacks for protobuf checks

tests/core/peer/test_envelope.py

@@ -0,0 +1,85 @@
+from multiaddr import Multiaddr
+
+from libp2p.crypto.rsa import (
+    create_new_key_pair,
+)
+from libp2p.peer.envelope import (
+    Envelope,
+    consume_envelope,
+    make_unsigned,
+    seal_record,
+    unmarshal_envelope,
+)
+from libp2p.peer.id import ID
+import libp2p.peer.pb.crypto_pb2 as crypto_pb
+import libp2p.peer.pb.envelope_pb2 as env_pb
+from libp2p.peer.peer_record import PeerRecord
+
+DOMAIN = "libp2p-peer-record"
+
+
+def test_basic_protobuf_serialization_deserialization():
+    pubkey = crypto_pb.PublicKey()  # type: ignore[attr-defined]
+    pubkey.Type = crypto_pb.KeyType.Ed25519  # type: ignore[attr-defined]
+    pubkey.Data = b"\x01\x02\x03"
+
+    env = env_pb.Envelope()  # type: ignore[attr-defined]
+    env.public_key.CopyFrom(pubkey)
+    env.payload_type = b"\x03\x01"
+    env.payload = b"test-payload"
+    env.signature = b"signature-bytes"
+
+    serialized = env.SerializeToString()
+
+    new_env = env_pb.Envelope()  # type: ignore[attr-defined]
+    new_env.ParseFromString(serialized)
+
+    assert new_env.public_key.Type == crypto_pb.KeyType.Ed25519  # type: ignore[attr-defined]
+    assert new_env.public_key.Data == b"\x01\x02\x03"
+    assert new_env.payload_type == b"\x03\x01"
+    assert new_env.payload == b"test-payload"
+    assert new_env.signature == b"signature-bytes"
+
+
+def test_enevelope_marshal_unmarshal_roundtrip():
+    keypair = create_new_key_pair()
+    pubkey = keypair.public_key
+    private_key = keypair.private_key
+
+    payload_type = b"\x03\x01"
+    payload = b"test-record"
+    sig = private_key.sign(make_unsigned(DOMAIN, payload_type, payload))
+
+    env = Envelope(pubkey, payload_type, payload, sig)
+    serialized = env.marshal_envelope()
+    new_env = unmarshal_envelope(serialized)
+
+    assert new_env.public_key == pubkey
+    assert new_env.payload_type == payload_type
+    assert new_env.raw_payload == payload
+    assert new_env.signature == sig
+
+
+def test_seal_and_consume_envelope_roundtrip():
+    keypair = create_new_key_pair()
+    priv_key = keypair.private_key
+    pub_key = keypair.public_key
+
+    peer_id = ID.from_pubkey(pub_key)
+    addrs = [Multiaddr("/ip4/127.0.0.1/tcp/4001"), Multiaddr("/ip4/127.0.0.1/tcp/4002")]
+    seq = 12345
+
+    record = PeerRecord(peer_id=peer_id, addrs=addrs, seq=seq)
+
+    # Seal
+    envelope = seal_record(record, priv_key)
+    serialized = envelope.marshal_envelope()
+
+    # Consume
+    env, rec = consume_envelope(serialized, record.domain())
+
+    # Assertions
+    assert env.public_key == pub_key
+    assert rec.peer_id == peer_id
+    assert rec.seq == seq
+    assert rec.addrs == addrs