node/test/parallel/test-net-socket-write-after-close.js

'use strict';
const common = require('../common');
const assert = require('assert');
const net = require('net');

{
  const server = net.createServer();

  server.listen(common.mustCall(() => {
    const port = server.address().port;
    const client = net.connect({port}, common.mustCall(() => {
      client.on('error', common.mustCall((err) => {
        server.close();
        assert.strictEqual(err.constructor, Error);
        assert.strictEqual(err.message, 'write EBADF');
      }));
      client._handle.close();
      client.write('foo');
    }));
  }));
}

{
  const server = net.createServer();

  server.listen(common.mustCall(() => {
    const port = server.address().port;
    const client = net.connect({port}, common.mustCall(() => {
      client.on('error', common.mustCall((err) => {
        server.close();
        assert.strictEqual(err.constructor, Error);
        assert.strictEqual(err.message, 'This socket is closed');
      }));
      client._handle.close();
      client._handle = null;
      client.write('foo');
    }));
  }));
}