src/process/bounded-line-framer.test.ts

import { describe, expect, it } from "vitest";
import { createBoundedLineFramer } from "./bounded-line-framer.js";

describe("bounded line framing", () => {
  it("preserves bytes, empty lines, and CR across arbitrary chunk boundaries", () => {
    const lines = [Buffer.from("漢😀\r"), Buffer.alloc(0), Buffer.from([0xff])];
    const wire = Buffer.concat(lines.flatMap((line) => [line, Buffer.from("\n")]));
    const framer = createBoundedLineFramer(8, "line too long");
    const received: Buffer[] = [];

    for (const byte of wire) {
      received.push(...framer.push(Buffer.from([byte])));
    }

    expect(received).toEqual(lines);
  });

  it("does not inspect a later oversized frame after its consumer retires", () => {
    const framer = createBoundedLineFramer(4, "line too long");
    const received: Buffer[] = [];

    for (const line of framer.push(Buffer.from("done\noversized"))) {
      received.push(line);
      break;
    }

    expect(received).toEqual([Buffer.from("done")]);
  });
});