node/lib/assert.js

// Originally from narwhal.js (http://narwhaljs.org)
// Copyright (c) 2009 Thomas Robinson <280north.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the 'Software'), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

'use strict';

const { compare } = process.binding('buffer');
const util = require('util');
const Buffer = require('buffer').Buffer;
const pToString = (obj) => Object.prototype.toString.call(obj);

// The assert module provides functions that throw
// AssertionError's when particular conditions are not met. The
// assert module must conform to the following interface.

const assert = module.exports = ok;

// The AssertionError is defined in assert.
// new assert.AssertionError({ message: message,
//                             actual: actual,
//                             expected: expected });

assert.AssertionError = function AssertionError(options) {
  this.name = 'AssertionError';
  this.actual = options.actual;
  this.expected = options.expected;
  this.operator = options.operator;
  if (options.message) {
    this.message = options.message;
    this.generatedMessage = false;
  } else {
    this.message = getMessage(this);
    this.generatedMessage = true;
  }
  const stackStartFunction = options.stackStartFunction || fail;
  Error.captureStackTrace(this, stackStartFunction);
};

// assert.AssertionError instanceof Error
util.inherits(assert.AssertionError, Error);

function truncate(s, n) {
  return s.slice(0, n);
}

function getMessage(self) {
  return truncate(util.inspect(self.actual), 128) + ' ' +
         self.operator + ' ' +
         truncate(util.inspect(self.expected), 128);
}

// At present only the three keys mentioned above are used and
// understood by the spec. Implementations or sub modules can pass
// other keys to the AssertionError's constructor - they will be
// ignored.

// All of the following functions must throw an AssertionError
// when a corresponding condition is not met, with a message that
// may be undefined if not provided. All assertion methods provide
// both the actual and expected values to the assertion error for
// display purposes.

function fail(actual, expected, message, operator, stackStartFunction) {
  if (arguments.length === 1)
    message = actual;
  if (arguments.length === 2)
    operator = '!=';
  throw new assert.AssertionError({
    message: message,
    actual: actual,
    expected: expected,
    operator: operator,
    stackStartFunction: stackStartFunction
  });
}
assert.fail = fail;

// Pure assertion tests whether a value is truthy, as determined
// by !!value.
function ok(value, message) {
  if (!value) fail(value, true, message, '==', ok);
}
assert.ok = ok;

// The equality assertion tests shallow, coercive equality with ==.
/* eslint-disable no-restricted-properties */
assert.equal = function equal(actual, expected, message) {
  if (actual != expected) fail(actual, expected, message, '==', assert.equal);
};

// The non-equality assertion tests for whether two objects are not
// equal with !=.
assert.notEqual = function notEqual(actual, expected, message) {
  if (actual == expected) {
    fail(actual, expected, message, '!=', notEqual);
  }
};

// The equivalence assertion tests a deep equality relation.
assert.deepEqual = function deepEqual(actual, expected, message) {
  if (!innerDeepEqual(actual, expected, false)) {
    fail(actual, expected, message, 'deepEqual', deepEqual);
  }
};
/* eslint-enable */

assert.deepStrictEqual = function deepStrictEqual(actual, expected, message) {
  if (!innerDeepEqual(actual, expected, true)) {
    fail(actual, expected, message, 'deepStrictEqual', deepStrictEqual);
  }
};

function innerDeepEqual(actual, expected, strict, memos) {
  // All identical values are equivalent, as determined by ===.
  if (actual === expected) {
    return true;

  // If both values are instances of buffers, equivalence is
  // determined by comparing the values and ensuring the result
  // === 0.
  } else if (actual instanceof Buffer && expected instanceof Buffer) {
    return compare(actual, expected) === 0;

  // If the expected value is a Date object, the actual value is
  // equivalent if it is also a Date object that refers to the same time.
  } else if (util.isDate(actual) && util.isDate(expected)) {
    return actual.getTime() === expected.getTime();

  // If the expected value is a RegExp object, the actual value is
  // equivalent if it is also a RegExp object with the same source and
  // properties (`global`, `multiline`, `lastIndex`, `ignoreCase`).
  } else if (util.isRegExp(actual) && util.isRegExp(expected)) {
    return actual.source === expected.source &&
           actual.global === expected.global &&
           actual.multiline === expected.multiline &&
           actual.lastIndex === expected.lastIndex &&
           actual.ignoreCase === expected.ignoreCase;

  // If both values are primitives, equivalence is determined by
  // == or, if checking for strict equivalence, ===.
  } else if ((actual === null || typeof actual !== 'object') &&
             (expected === null || typeof expected !== 'object')) {
    return strict ? actual === expected : actual == expected;

  // If both values are instances of typed arrays, wrap their underlying
  // ArrayBuffers in a Buffer to increase performance.
  // This optimization requires the arrays to have the same type as checked by
  // Object.prototype.toString (pToString). Never perform binary
  // comparisons for Float*Arrays, though, since +0 === -0 is true despite the
  // two values' bit patterns not being identical.
  } else if (ArrayBuffer.isView(actual) && ArrayBuffer.isView(expected) &&
             pToString(actual) === pToString(expected) &&
             !(actual instanceof Float32Array ||
               actual instanceof Float64Array)) {
    return compare(Buffer.from(actual.buffer,
                               actual.byteOffset,
                               actual.byteLength),
                   Buffer.from(expected.buffer,
                               expected.byteOffset,
                               expected.byteLength)) === 0;

  // For all other Object pairs, including Array objects, equivalence is
  // determined by having the same number of owned properties (as verified
  // with Object.prototype.hasOwnProperty.call), the same set of keys
  // (although not necessarily the same order), equivalent values for every
  // corresponding key, and an identical 'prototype' property. Note: this
  // accounts for both named and indexed properties on Arrays.
  } else {
    memos = memos || {actual: [], expected: []};

    const actualIndex = memos.actual.indexOf(actual);
    if (actualIndex !== -1) {
      if (actualIndex === memos.expected.indexOf(expected)) {
        return true;
      }
    }

    memos.actual.push(actual);
    memos.expected.push(expected);

    return objEquiv(actual, expected, strict, memos);
  }
}

function isArguments(object) {
  return Object.prototype.toString.call(object) === '[object Arguments]';
}

function objEquiv(a, b, strict, actualVisitedObjects) {
  if (a === null || a === undefined || b === null || b === undefined)
    return false;

  // If one is a primitive, the other must be the same.
  if (util.isPrimitive(a) || util.isPrimitive(b))
    return a === b;
  if (strict && Object.getPrototypeOf(a) !== Object.getPrototypeOf(b))
    return false;
  const aIsArgs = isArguments(a);
  const bIsArgs = isArguments(b);
  if ((aIsArgs && !bIsArgs) || (!aIsArgs && bIsArgs))
    return false;
  const ka = Object.keys(a);
  const kb = Object.keys(b);
  var key, i;

  // The pair must have the same number of owned properties (keys
  // incorporates hasOwnProperty).
  if (ka.length !== kb.length)
    return false;

  // The pair must have the same set of keys (although not
  // necessarily in the same order).
  ka.sort();
  kb.sort();
  // Cheap key test:
  for (i = ka.length - 1; i >= 0; i--) {
    if (ka[i] !== kb[i])
      return false;
  }
  // The pair must have equivalent values for every corresponding key.
  // Possibly expensive deep test:
  for (i = ka.length - 1; i >= 0; i--) {
    key = ka[i];
    if (!innerDeepEqual(a[key], b[key], strict, actualVisitedObjects))
      return false;
  }
  return true;
}

// The non-equivalence assertion tests for any deep inequality.
assert.notDeepEqual = function notDeepEqual(actual, expected, message) {
  if (innerDeepEqual(actual, expected, false)) {
    fail(actual, expected, message, 'notDeepEqual', notDeepEqual);
  }
};

assert.notDeepStrictEqual = notDeepStrictEqual;
function notDeepStrictEqual(actual, expected, message) {
  if (innerDeepEqual(actual, expected, true)) {
    fail(actual, expected, message, 'notDeepStrictEqual',
         notDeepStrictEqual);
  }
}


// The strict equality assertion tests strict equality, as determined by ===.
assert.strictEqual = function strictEqual(actual, expected, message) {
  if (actual !== expected) {
    fail(actual, expected, message, '===', strictEqual);
  }
};

// The strict non-equality assertion tests for strict inequality, as
// determined by !==.
assert.notStrictEqual = function notStrictEqual(actual, expected, message) {
  if (actual === expected) {
    fail(actual, expected, message, '!==', notStrictEqual);
  }
};

function expectedException(actual, expected) {
  // actual is guaranteed to be an Error object, but we need to check expected.
  if (!expected) {
    return false;
  }

  if (Object.prototype.toString.call(expected) === '[object RegExp]') {
    return expected.test(actual);
  }

  try {
    if (actual instanceof expected) {
      return true;
    }
  } catch (e) {
    // Ignore. The instanceof check doesn't work for arrow functions.
  }

  if (Error.isPrototypeOf(expected)) {
    return false;
  }

  return expected.call({}, actual) === true;
}

function tryBlock(block) {
  var error;
  try {
    block();
  } catch (e) {
    error = e;
  }
  return error;
}

function innerThrows(shouldThrow, block, expected, message) {
  if (typeof block !== 'function') {
    throw new TypeError('"block" argument must be a function');
  }

  if (typeof expected === 'string') {
    message = expected;
    expected = null;
  }

  const actual = tryBlock(block);

  message = (expected && expected.name ? ' (' + expected.name + ').' : '.') +
            (message ? ' ' + message : '.');

  if (shouldThrow && !actual) {
    fail(actual, expected, 'Missing expected exception' + message, fail);
  }

  const userProvidedMessage = typeof message === 'string';
  const isUnwantedException = !shouldThrow && util.isError(actual);
  const isUnexpectedException = !shouldThrow && actual && !expected;

  if ((isUnwantedException &&
      userProvidedMessage &&
      expectedException(actual, expected)) ||
      isUnexpectedException) {
    fail(actual, expected, 'Got unwanted exception' + message, fail);
  }

  if ((shouldThrow && actual && expected &&
      !expectedException(actual, expected)) || (!shouldThrow && actual)) {
    throw actual;
  }
}

// Expected to throw an error.
assert.throws = function throws(block, error, message) {
  innerThrows(true, block, error, message);
};

assert.doesNotThrow = function doesNotThrow(block, error, message) {
  innerThrows(false, block, error, message);
};

assert.ifError = function ifError(err) { if (err) throw err; };