1 files changed, 57 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/expressions/await/await-non-promise-thenable.js b/js/src/tests/test262/language/expressions/await/await-non-promise-thenable.js
new file mode 100644
index 0000000000..bad7cc6776
--- /dev/null
+++ b/js/src/tests/test262/language/expressions/await/await-non-promise-thenable.js
@@ -0,0 +1,57 @@
+// |reftest| async
+// 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 "then" on a non-native promise
+  will still get called.
+flags: [async]
+features: [async-functions]
+includes: [compareArray.js]
+---*/
+
+let thenCallCount = 0;
+
+const actual = [];
+const expected = [
+  'Promise: 1',
+  'Promise: 2',
+  'Await: 1',
+  'Promise: 3',
+  'Promise: 4',
+  'Await: 2',
+];
+
+const patched = {};
+patched.then = function(fulfill, reject) {
+  thenCallCount++;
+  fulfill(thenCallCount);
+};
+
+async function trigger() {
+  actual.push('Await: ' + await patched);
+  actual.push('Await: ' + await patched);
+}
+
+function checkAssertions() {
+  assert.compareArray(actual, expected,
+    'Async/await and promises should be interleaved');
+  assert.sameValue(thenCallCount, 2,
+    '"then" on non-native promises should be called.');
+}
+
+trigger().then(checkAssertions).then($DONE, $DONE);
+
+new Promise(function (resolve) {
+  actual.push('Promise: 1');
+  resolve();
+}).then(function () {
+  actual.push('Promise: 2');
+}).then(function () {
+  actual.push('Promise: 3');
+}).then(function () {
+  actual.push('Promise: 4');
+});