sim

Integration simulation tests for EdgeSync. Real NATS, real Fossil, real leaf and bridge binaries — wrapped in a deterministic harness with a TCP fault-injection proxy.

Lives in the root module: github.com/danmestas/EdgeSync/sim. (Deterministic single-threaded sim tests live in libfossil's dst/ — see ADR notes in the root README.md.)

What it does

• TCP fault proxy (proxy.go) — drops, delays, partitions, and corrupts traffic between NATS, leaf, and bridge processes. Seeded RNG drives the schedule.
• Harness (harness.go) — starts processes, points them at the proxy, asserts invariants on convergence.
• Serve tests (serve_test.go) — exercise fossil clone and fossil sync against the leaf's ServeHTTP; verify a stock Fossil binary is a valid client.
• Interop tests (interop_test.go, diff_interop_test.go, finfo_interop_test.go) — Tier-1 byte-equivalence and Tier-2 sampling against reference Fossil checkouts.
• BUGGIFY (buggify.go) — stochastic fault injection inside libfossil's sync loop, gated by sync.BuggifyChecker.
• Iroh tests (iroh_test.go, nats_iroh_test.go) — leaf-to-leaf over the iroh sidecar; full QUIC + Unix-socket lifecycle.
• Soak runner (cmd/soak/) — continuous random-seed runner for catching rare schedules.

How to run

make sim         # 1 seed, normal severity, ~1m
make sim-full    # 16 seeds × 3 severities (normal/adversarial/hostile), ~30m
make test-interop  # Tier-1 + Tier-2, requires `fossil` binary on PATH
make test-iroh   # build iroh-sidecar then run iroh tests

Direct: cd sim && go test . -run TestSimulation -sim.seed=N -sim.severity=hostile -timeout=120s.

Where it fits

Sim is the integration-tier test bench: it boots real binaries with fault injection. Faster deterministic single-threaded tests (DST) live in libfossil. Per-module unit tests live alongside their code (leaf/..., bridge/...).

See docs/architecture/testing-strategy.md for the test pyramid.