test262/test/language/expressions/await/await-monkey-patched-promis...

51 lines
1.2 KiB
JavaScript

// Copyright 2018 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
author: Maya Lekova <mslekova@chromium.org>
esid: await
description: >
This test demonstrates that monkey-patched "then" on native promises will
not get called. Adapted from example by Kevin Smith:
https://github.com/tc39/ecma262/pull/1250#issuecomment-401082195
flags: [async]
features: [async-functions]
includes: [compareArray.js]
---*/
let thenCallCount = 0;
const value = 42;
const actual = [];
const expected = [
'Promise: 1',
'Await: ' + value,
'Promise: 2',
];
const patched = Promise.resolve(value);
patched.then = function(...args) {
thenCallCount++;
Promise.prototype.then.apply(this, args);
};
async function trigger() {
actual.push('Await: ' + await patched);
}
function checkAssertions() {
assert.compareArray(actual, expected,
'Async/await and promises should be interleaved');
assert.sameValue(thenCallCount, 0,
'Monkey-patched "then" on native promises should not be called.')
}
trigger().then(checkAssertions).then($DONE, $DONE);
new Promise(function (resolve) {
actual.push('Promise: 1');
resolve();
}).then(function () {
actual.push('Promise: 2');
});