1 files changed, 45 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/expressions/await/async-await-interleaved.js b/js/src/tests/test262/language/expressions/await/async-await-interleaved.js
new file mode 100644
index 0000000000..16ef6cad4f
--- /dev/null
+++ b/js/src/tests/test262/language/expressions/await/async-await-interleaved.js
@@ -0,0 +1,45 @@
+// |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: >
+  Await on async functions and builtin Promises are properly interleaved,
+  meaning await takes only 1 tick on the microtask queue.
+flags: [async]
+features: [async-functions]
+includes: [compareArray.js]
+---*/
+
+const actual = [];
+const expected = [
+  'Await: 1',
+  'Promise: 1',
+  'Await: 2',
+  'Promise: 2'
+];
+
+async function pushAwait(value) {
+  actual.push('Await: ' + value);
+}
+
+async function callAsync() {
+  await pushAwait(1);
+  await pushAwait(2);
+}
+
+function checkAssertions() {
+  assert.compareArray(actual, expected,
+    'Async/await and promises should be interleaved');
+}
+
+callAsync();
+
+new Promise(function (resolve) {
+  actual.push('Promise: 1');
+  resolve();
+}).then(function () {
+  actual.push('Promise: 2');
+}).then(checkAssertions).then($DONE, $DONE);