Test Harness Guide

This test suite uses an in-memory networking harness to make end-to-end and integration tests deterministic, fast, and race-free without touching production code.

In-Memory Bus

• File: bitchatTests/Mocks/MockBLEService.swift
• Registry/Adjacency: Global registry maps peerID to a MockBLEService instance; adjacency records simulated links between peers.
• Setup: Call MockBLEService.resetTestBus() in setUp() to clear state between tests.
• Topology: Use simulateConnectedPeer(_:) and simulateDisconnectedPeer(_:) to add/remove links. connectFullMesh() helpers in tests build larger topologies.
• Handlers: Tests can observe data via messageDeliveryHandler (decoded BitchatMessage) and packetDeliveryHandler (raw BitchatPacket).
• De‑duplication: A thread-safe seenMessageIDs prevents duplicate deliveries during flooding/relays.

Broadcast Flooding

• Flag: MockBLEService.autoFloodEnabled
• Intent: When true, public broadcasts propagate across the entire connected component (ignores TTL for reach) while still de‑duping to prevent loops.
• Usage: Enabled in Integration tests (setUp) to simulate large-network broadcast; disabled in E2E tests to keep routing explicit and verify TTL behavior (see PublicChatE2ETests.testZeroTTLNotRelayed).

Rehandshake Flow (Noise)

• Why: The legacy NACK recovery path was removed; recovery now relies on Noise session rehandshake after decrypt failure or desync.
• Manager: NoiseSessionManager manages per-peer sessions.
• Pattern: On decrypt failure, proactively clear the local session and re-initiate a handshake. The peer accepts and replaces their session.
• Test: IntegrationTests.testRehandshakeAfterDecryptionFailure
  • Corrupts ciphertext to induce a decrypt error.
  • Calls removeSession(for:) on the initiator’s manager before initiateHandshake(with:) to avoid alreadyEstablished.
  • Verifies encrypt/decrypt succeeds post-rehandshake.

Tips

• Determinism: Add small async delays only where handler installation/topology changes could race the first send.
• Scoping: Keep autoFloodEnabled toggled only within Integration tests; always reset in tearDown() to avoid cross-test contamination.
• Direct vs Relay: Private messages target a specific peer when adjacent; otherwise they are surfaced to neighbors for relay and, if known, also delivered to the target.

Quick Start

• Create nodes and connect them:
  • let svc = MockBLEService(); svc.myPeerID = "PEER1"
  • svc.simulateConnectedPeer("PEER2")
• Observe messages:
  • svc.messageDeliveryHandler = { msg in /* asserts */ }
• Enable broadcast flooding for Integration suites only:
  • MockBLEService.autoFloodEnabled = true