test/parallel/test-stream-writable-end-multiple.js

'use strict';

const common = require('../common');

const assert = require('assert');
const stream = require('stream');

const writable = new stream.Writable();
writable._write = (chunk, encoding, cb) => {
  setTimeout(() => cb(), 10);
};

writable.end('testing ended state', common.mustCall());
writable.end(common.mustCall());
writable.on('finish', common.mustCall(() => {
  let ticked = false;
  writable.end(common.mustCall((err) => {
    assert.strictEqual(ticked, true);
    assert.strictEqual(err.code, 'ERR_STREAM_ALREADY_FINISHED');
  }));
  ticked = true;
}));