Multiplayer, Network, and Online Services Testing
What this domain tests
This domain tests networked play and service dependencies under realistic conditions: matchmaking, sessions, latency, packet loss, host migration, and backend services.
Core rules
- Topologies include client-server, dedicated server, listen server, and peer-to-peer. Each has different authority and failure modes.
- Simulate network conditions: latency, jitter, packet loss, bandwidth caps, NAT types, and relay versus direct connections.
- Test the session lifecycle: create, join, invite, ready, start, migrate host, leave, reconnect, and teardown.
- Service dependencies include authentication, entitlements, leaderboards, cloud saves, telemetry, and anti-cheat. Test outage and degraded modes, not only healthy services.
- Verify server authority: clients must not duplicate items, speed hack, or desynchronize state.
Worked example
A co-op boss fight runs at 200 ms latency and 5% packet loss. Expected: hit registration resolves through server authority, no rubber-banding beyond the simulated conditions, and host migration if the host drops. Actual: the client shows damage but the server rejects it. The reasoning is that this is a reconciliation or authority mismatch, not generic lag. Reproduce with client and server logs plus timestamps to show the rejected event.
Traps
Testing only on a LAN; ignoring host migration and reconnect; skipping cross-play and mixed input devices; assuming it works on my NAT is sufficient; not testing service outages; failing to distinguish client prediction from server truth.