node/test/parallel/test-assert-fail-deprecation.js

'use strict';

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

common.expectWarning(
  'DeprecationWarning',
  'assert.fail() with more than one argument is deprecated. ' +
    'Please use assert.strictEqual() instead or only pass a message.'
);

// Two args only, operator defaults to '!='
assert.throws(() => {
  assert.fail('first', 'second');
}, {
  code: 'ERR_ASSERTION',
  name: 'AssertionError [ERR_ASSERTION]',
  message: '\'first\' != \'second\'',
  operator: '!=',
  actual: 'first',
  expected: 'second'
});

// Three args
assert.throws(() => {
  assert.fail('ignored', 'ignored', 'another custom message');
}, {
  code: 'ERR_ASSERTION',
  name: 'AssertionError [ERR_ASSERTION]',
  message: 'another custom message',
  operator: undefined,
  actual: 'ignored',
  expected: 'ignored'
});

// Three args with custom Error
assert.throws(() => {
  assert.fail(typeof 1, 'object', new TypeError('another custom message'));
}, {
  name: 'TypeError',
  message: 'another custom message'
});

// No third arg (but a fourth arg)
assert.throws(() => {
  assert.fail('first', 'second', undefined, 'operator');
}, {
  code: 'ERR_ASSERTION',
  name: 'AssertionError [ERR_ASSERTION]',
  message: '\'first\' operator \'second\'',
  operator: 'operator',
  actual: 'first',
  expected: 'second'
});

// The stackFrameFunction should exclude the foo frame
assert.throws(
  function foo() { assert.fail('first', 'second', 'message', '!==', foo); },
  (err) => !/^\s*at\sfoo\b/m.test(err.stack)
);