Function testDestroyDuringBackpressure

test/parallel/test-stream-iter-to-readable.js:177–204

()

// =============================================================================

async function testDestroyDuringBackpressure() {
  let returnCalled = false;
  async function* gen() {
    try {
      // Yield a large batch that will trigger backpressure with HWM=1
      yield [Buffer.from('a'), Buffer.from('b'), Buffer.from('c')];
      // This should never be reached
      yield [Buffer.from('d')];
    } finally {
      returnCalled = true;
    }
  }

  const readable = toReadable(gen(), { highWaterMark: 1 });

  // Read one chunk to start the pump, then destroy while it's waiting
  const chunk = await new Promise((resolve) => {
    readable.once('readable', () => resolve(readable.read()));
  });
  assert.ok(chunk);

  // The pump should be waiting on backpressure now. Destroy the stream.
  readable.destroy();

  await new Promise((resolve) => readable.on('close', resolve));
  assert.ok(readable.destroyed);
  assert.ok(returnCalled, 'iterator.return() should have been called');
}

// =============================================================================
// fromStreamIter: large data integrity