node/test/parallel/test-cli-eval.js

'use strict';
if (module.parent) {
  // Signal we've been loaded as a module.
  // The following console.log() is part of the test.
  console.log('Loaded as a module, exiting with status code 42.');
  process.exit(42);
}

const common = require('../common');
const assert = require('assert');
const child = require('child_process');
const path = require('path');
const nodejs = `"${process.execPath}"`;

// Assert that nothing is written to stdout.
child.exec(`${nodejs} --eval 42`, common.mustCall((err, stdout, stderr) => {
  assert.ifError(err);
  assert.strictEqual(stdout, '');
  assert.strictEqual(stderr, '');
}));

// Assert that "42\n" is written to stderr.
child.exec(`${nodejs} --eval "console.error(42)"`,
           common.mustCall((err, stdout, stderr) => {
             assert.ifError(err);
             assert.strictEqual(stdout, '');
             assert.strictEqual(stderr, '42\n');
           }));

// Assert that the expected output is written to stdout.
['--print', '-p -e', '-pe', '-p'].forEach((s) => {
  const cmd = `${nodejs} ${s} `;

  child.exec(`${cmd}42`, common.mustCall((err, stdout, stderr) => {
    assert.ifError(err);
    assert.strictEqual(stdout, '42\n');
    assert.strictEqual(stderr, '');
  }));

  child.exec(`${cmd} '[]'`, common.mustCall((err, stdout, stderr) => {
    assert.ifError(err);
    assert.strictEqual(stdout, '[]\n');
    assert.strictEqual(stderr, '');
  }));
});

// Assert that module loading works.
{
  // Replace \ by / because Windows uses backslashes in paths, but they're still
  // interpreted as the escape character when put between quotes.
  const filename = __filename.replace(/\\/g, '/');

  child.exec(`${nodejs} --eval "require('${filename}')"`,
             common.mustCall((err, stdout, stderr) => {
               assert.strictEqual(err.code, 42);
               assert.strictEqual(
                 stdout, 'Loaded as a module, exiting with status code 42.\n');
               assert.strictEqual(stderr, '');
             }));
}

// Check that builtin modules are pre-defined.
child.exec(`${nodejs} --print "os.platform()"`,
           common.mustCall((err, stdout, stderr) => {
             assert.ifError(err);
             assert.strictEqual(stderr, '');
             assert.strictEqual(stdout.trim(), require('os').platform());
           }));

// Module path resolve bug regression test.
child.exec(`${nodejs} --eval "require('./test/parallel/test-cli-eval.js')"`,
           common.mustCall((err, stdout, stderr) => {
             assert.strictEqual(err.code, 42);
             assert.strictEqual(
               stdout, 'Loaded as a module, exiting with status code 42.\n');
             assert.strictEqual(stderr, '');
           }));

// Missing argument should not crash.
child.exec(`${nodejs} -e`, common.mustCall((err, stdout, stderr) => {
  assert.strictEqual(err.code, 9);
  assert.strictEqual(stdout, '');
  assert.strictEqual(stderr.trim(),
                     `${process.execPath}: -e requires an argument`);
}));

// Empty program should do nothing.
child.exec(`${nodejs} -e ""`, common.mustCall((err, stdout, stderr) => {
  assert.ifError(err);
  assert.strictEqual(stdout, '');
  assert.strictEqual(stderr, '');
}));

// "\\-42" should be interpreted as an escaped expression, not a switch.
child.exec(`${nodejs} -p "\\-42"`, common.mustCall((err, stdout, stderr) => {
  assert.ifError(err);
  assert.strictEqual(stdout, '-42\n');
  assert.strictEqual(stderr, '');
}));

child.exec(`${nodejs} --use-strict -p process.execArgv`,
           common.mustCall((err, stdout, stderr) => {
             assert.ifError(err);
             assert.strictEqual(
               stdout, "[ '--use-strict', '-p', 'process.execArgv' ]\n"
             );
             assert.strictEqual(stderr, '');
           }));

// Regression test for https://github.com/nodejs/node/issues/3574.
{
  const emptyFile = path.join(common.fixturesDir, 'empty.js');

  child.exec(`${nodejs} -e 'require("child_process").fork("${emptyFile}")'`,
             common.mustCall((err, stdout, stderr) => {
               assert.ifError(err);
               assert.strictEqual(stdout, '');
               assert.strictEqual(stderr, '');
             }));

  // Make sure that monkey-patching process.execArgv doesn't cause child_process
  // to incorrectly munge execArgv.
  child.exec(
    `${nodejs} -e "process.execArgv = ['-e', 'console.log(42)', 'thirdArg'];` +
                  `require('child_process').fork('${emptyFile}')"`,
    common.mustCall((err, stdout, stderr) => {
      assert.ifError(err);
      assert.strictEqual(stdout, '42\n');
      assert.strictEqual(stderr, '');
    }));
}

// Regression test for https://github.com/nodejs/node/issues/8534.
{
  const script = `
      // console.log() can revive the event loop so we must be careful
      // to write from a 'beforeExit' event listener only once.
      process.once("beforeExit", () => console.log("beforeExit"));
      process.on("exit", () => console.log("exit"));
      console.log("start");
  `;
  const options = { encoding: 'utf8' };
  const proc = child.spawnSync(process.execPath, ['-e', script], options);
  assert.strictEqual(proc.stderr, '');
  assert.strictEqual(proc.stdout, 'start\nbeforeExit\nexit\n');
}