import test from "node:test";
import assert from "node:assert/strict";

import { createSerializedRunner } from "../local-agent/serialized-runner.mjs";

test("createSerializedRunner coalesces overlapping calls into the same promise", async () => {
  let runs = 0;
  let release;
  const gate = new Promise((resolve) => {
    release = resolve;
  });

  const runner = createSerializedRunner(async () => {
    runs += 1;
    await gate;
    return { runs };
  });

  const first = runner();
  const second = runner();
  assert.equal(first, second);
  assert.equal(runs, 1);

  release();
  const result = await first;
  assert.deepEqual(result, { runs: 1 });
});

test("createSerializedRunner allows the next call after the current run finishes", async () => {
  let runs = 0;
  const runner = createSerializedRunner(async () => {
    runs += 1;
    return runs;
  });

  assert.equal(await runner(), 1);
  assert.equal(await runner(), 2);
  assert.equal(runs, 2);
});