TwitchBot/node_modules/mysql/test/integration/connection/test-exception-safety.js

// This test covers all event / callback interfaces offered by node-mysql and
// throws an exception in them. Exception safety means that each of those
// exceptions can be caught by an 'uncaughtException' / Domain handler without
// the connection instance ending up in a bad state where it doesn't work
// properly or doesn't execute the next sequence anymore.

var common     = require('../../common');
var connection = common.createConnection();
var assert     = require('assert');


var errors = [];
process.on('uncaughtException', function(err) {
  console.log(err.stack);
  errors.push(err);
});

// Normal callback
connection.connect(function(err) {
  throw err || new Error('1');
});

// Normal callback (same code path as connect, but in here should that
// implementation detail change at some point).
connection.query('SELECT 1', function(err) {
  throw err || new Error('2');
});

// Row streaming events
connection.query('SELECT 1')
  .on('fields', function() {
    throw new Error('3');
  })
  .on('result', function() {
    throw new Error('4');
  });

// Normal callback with error
connection.query('INVALID SQL', function(err) {
  assert.equal(err.code, 'ER_PARSE_ERROR');

  throw new Error('5');
});

// Row streaming 'result' event triggered by Ok Packet (special code path)
connection.query('USE ' + common.testDatabase)
  .on('result', function() {
    throw new Error('6');
  });

// Normal callback (same code path as connect, but in here should that
// implementation detail change at some point).
connection.end(function(err) {
  throw err || new Error('7');
});

process.on('exit', function() {
  process.removeAllListeners();

  var expectedErrors = 7;
  for (var i = 0; i < expectedErrors - 1; i++) {
    var error = errors[i];
    assert.equal(error.message, String(i + 1));
    assert.equal(error.code, undefined);
  }
});