build_message

async def build_message(
    message: "SendableMessage",
    topic: str,
    *,
    correlation_id: str | None = None,
    partition: int | None = None,
    timestamp_ms: int | None = None,
    key: bytes | str | None = None,
    headers: dict[str, str] | None = None,
    reply_to: str = "",
    serializer: Optional["SerializerProto"] = None,
    codec: Optional["CodecProto"] = None,
    id_generator: IdGenerator = gen_cor_id,
) -> MockConfluentMessage:
    """Build a mock confluent_kafka.Message for a sendable message."""
    if message is None:
        # keep a real tombstone (message.value() is None) distinct from b""
        msg, content_type = None, None
    else:
        codec_instance = codec or DefaultCodec()
        msg, content_type = await codec_instance.encode(message, serializer)
    k = key or b""
    headers = {
        "content-type": content_type or "",
        "correlation_id": correlation_id or id_generator(),
        "reply_to": reply_to,
        **(headers or {}),
    }

    # https://docs.confluent.io/platform/current/clients/confluent-kafka-python/html/index.html#confluent_kafka.Message.timestamp
    return MockConfluentMessage(
        raw_msg=msg,
        topic=topic,
        key=k,
        headers=[(i, j.encode()) for i, j in headers.items()],
        offset=0,
        partition=partition or 0,
        timestamp_type=1,
        timestamp_ms=timestamp_ms or int(datetime.now(timezone.utc).timestamp() * 1000),
    )