test_thenable_vs_promise_ordering.html

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<title>Test for promise resolution ordering with thenables and promises</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<div id="log"></div>

<script>

/* global async_test, assert_true, assert_equals */

var t = async_test("A promise resolved first (with a thenable) should trigger its callbacks before a promise resolved second (with a promise).");

t.step(function() {

  var customThenCalled = false;

  var p0 = Promise.resolve();

  p0.then = function(resolved, rejected) {

    customThenCalled = true;

    Promise.prototype.then.call(this, resolved, rejected);

};

  var p1 = new Promise(function(r) { r(p0); });

  delete p0.then;

  var p2 = new Promise(function(r) { r(p0); });

  var resolutionOrder = "";

  Promise.all([ p1.then(function() { resolutionOrder += "1"; }),

                p2.then(function() { resolutionOrder += "2"; }) ])

         .then(t.step_func_done(function() {

           assert_true(customThenCalled, "Should have called custom then");

           assert_equals(resolutionOrder, "12");

         }));

});

</script>