JSTests/test262/harness/assert.js

// Copyright (C) 2017 Ecma International.  All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
description: |
    Collection of assertion functions used throughout test262
defines: [assert]
---*/


function assert(mustBeTrue, message) {
  if (mustBeTrue === true) {
    return;
  }

  if (message === undefined) {
    message = 'Expected true but got ' + assert._toString(mustBeTrue);
  }
  $ERROR(message);
}

assert._isSameValue = function (a, b) {
  if (a === b) {
    // Handle +/-0 vs. -/+0
    return a !== 0 || 1 / a === 1 / b;
  }

  // Handle NaN vs. NaN
  return a !== a && b !== b;
};

assert.sameValue = function (actual, expected, message) {
  try {
    if (assert._isSameValue(actual, expected)) {
      return;
    }
  } catch (error) {
    $ERROR(message + ' (_isSameValue operation threw) ' + error);
    return;
  }

  if (message === undefined) {
    message = '';
  } else {
    message += ' ';
  }

  message += 'Expected SameValue(«' + assert._toString(actual) + '», «' + assert._toString(expected) + '») to be true';

  $ERROR(message);
};

assert.notSameValue = function (actual, unexpected, message) {
  if (!assert._isSameValue(actual, unexpected)) {
    return;
  }

  if (message === undefined) {
    message = '';
  } else {
    message += ' ';
  }

  message += 'Expected SameValue(«' + assert._toString(actual) + '», «' + assert._toString(unexpected) + '») to be false';

  $ERROR(message);
};

assert.throws = function (expectedErrorConstructor, func, message) {
  if (typeof func !== "function") {
    $ERROR('assert.throws requires two arguments: the error constructor ' +
      'and a function to run');
    return;
  }
  if (message === undefined) {
    message = '';
  } else {
    message += ' ';
  }

  try {
    func();
  } catch (thrown) {
    if (typeof thrown !== 'object' || thrown === null) {
      message += 'Thrown value was not an object!';
      $ERROR(message);
    } else if (thrown.constructor !== expectedErrorConstructor) {
      message += 'Expected a ' + expectedErrorConstructor.name + ' but got a ' + thrown.constructor.name;
      $ERROR(message);
    }
    return;
  }

  message += 'Expected a ' + expectedErrorConstructor.name + ' to be thrown but no exception was thrown at all';
  $ERROR(message);
};

assert._toString = function (value) {
  try {
    return String(value);
  } catch (err) {
    if (err.name === 'TypeError') {
      return Object.prototype.toString.call(value);
    }

    throw err;
  }
};