37 lines
1.4 KiB
JavaScript
37 lines
1.4 KiB
JavaScript
describe('Evil promises should not be able to break invariants', function () {
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'use strict';
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specify('resolving to a promise that calls onFulfilled twice', function (done) {
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// note that we have to create a trivial subclass, as otherwise the
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// Promise.resolve(evilPromise) is just the identity function.
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// (And in fact, most native Promise implementations use a private
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// [[PromiseConstructor]] field in `Promise.resolve` which can't be
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// easily patched in an ES5 engine, so instead of
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// `Promise.resolve(evilPromise)` we'll use
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// `new Promise(function(r){r(evilPromise);})` below.)
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var EvilPromise = function (executor) {
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var self = new Promise(executor);
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Object.setPrototypeOf(self, EvilPromise.prototype);
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return self;
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};
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if (!Object.setPrototypeOf) { return done(); } // skip test if on IE < 11
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Object.setPrototypeOf(EvilPromise, Promise);
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EvilPromise.prototype = Object.create(Promise.prototype, {
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constructor: { value: EvilPromise }
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});
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var evilPromise = EvilPromise.resolve();
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evilPromise.then = function (f) {
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f(1);
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f(2);
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};
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var calledAlready = false;
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new Promise(function (r) { r(evilPromise); }).then(function (value) {
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assert.strictEqual(calledAlready, false);
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calledAlready = true;
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assert.strictEqual(value, 1);
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}).then(done, done);
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});
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});
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