Function run_parser

tests/scripts/conftest.py:20–70

Execute a parser script's parse() function via Node.js. The frame_input is serialised as JSON and injected directly into the generated wrapper snippet, so both string and array inputs work without any type-specific encoding gymnastics. Args: script_name: Filename insid

(script_name: str, frame_input)

def run_parser(script_name: str, frame_input) -> list:
    """
    Execute a parser script's parse() function via Node.js.

    The frame_input is serialised as JSON and injected directly into the
    generated wrapper snippet, so both string and array inputs work without
    any type-specific encoding gymnastics.

    Args:
        script_name: Filename inside app/rcc/scripts/parser/js/ (e.g. "comma_separated.js")
        frame_input: String or list to pass as the frame argument to parse()

    Returns:
        The value returned by parse(), deserialised from JSON.

    Raises:
        RuntimeError: If Node.js exits with a non-zero status.
        json.JSONDecodeError: If the output cannot be parsed.
    """
    script_path = SCRIPTS_DIR / script_name
    script_source = script_path.read_text(encoding="utf-8")

    runner = f"""{script_source}
var _result = parse({json.dumps(frame_input)});
console.log(JSON.stringify(_result));
"""
    # Feed the program over stdin ("node -") instead of "node -e <src>": passing a
    # large script as an argv string trips the Windows 32767-char command-line limit
    # (subprocess surfaces it as "environment variable is longer than 32767").
    #
    # Pin encoding="utf-8": the parser scripts carry non-ASCII characters (e.g. the
    # U+2192 arrow in comments). Without this, text mode decodes/encodes with the
    # locale codec, which is cp1252 on the Windows runners and raises
    # UnicodeEncodeError when the script source crosses the subprocess boundary.
    result = subprocess.run(
        ["node", "-"],
        input=runner,
        capture_output=True,
        text=True,
        encoding="utf-8",
        timeout=30,
    )

    if result.returncode != 0:
        raise RuntimeError(
            f"Node.js exited {result.returncode} for {script_name}:\n{result.stderr}"
        )

    # Take the last non-empty line; earlier lines may be console.log() debug output
    last_line = result.stdout.strip().splitlines()[-1]
    return json.loads(last_line)


@pytest.fixture