elmulator: Python package

A pure-standard-library ELM327 TCP server and scenario validator. No third-party dependencies. Python 3.9+.

Install

pip install elmulator
# or from a checkout of this repo:
pip install -e .

If the elmulator command is not on your PATH after installing (pip prints a warning when the scripts directory is not on PATH), use python -m elmulator instead. It works the same way, for example python -m elmulator self-test.

CLI

elmulator serve SCENARIO [--host H] [--port N] [--echo on|off|scenario] \
                         [--split a,b,c] [--latency-ms N] [--jitter-ms N] [--seed N]
elmulator validate [PATHS...]     # files or dirs; defaults to the bundled examples
elmulator self-test               # in-process loopback smoke test

serve prints LISTENING <port> on stdout once bound (--port 0 picks a free port) and logs activity to stderr. Each client gets its own scenario cursor state.

Library

from elmulator import Scenario, serve
import argparse

scenario = Scenario.from_path("scenarios/p0420_basic.scenario.json")
args = argparse.Namespace(host="127.0.0.1", port=0, echo="scenario",
                          split=None, latency_ms=0, jitter_ms=0, seed=0)
serve(args, scenario)   # blocking; pass ready_event/stop_event for threaded use

The matching, echo, splitting, and jitter semantics are identical to the Swift engine; the conformance suite proves byte-for-byte parity.

Test

pip install pytest
pytest -q