1 files changed, 63 insertions, 0 deletions
diff --git a/js/src/tests/non262/AsyncIterator/prototype/lazy-methods-return-closes-iterator.js b/js/src/tests/non262/AsyncIterator/prototype/lazy-methods-return-closes-iterator.js
new file mode 100644
index 0000000000..98a0902b75
--- /dev/null
+++ b/js/src/tests/non262/AsyncIterator/prototype/lazy-methods-return-closes-iterator.js
@@ -0,0 +1,63 @@
+// |reftest| skip-if(!this.hasOwnProperty('AsyncIterator'))
+
+//
+//
+/*---
+esid: pending
+description: Calling `return` on a lazy %AsyncIterator.prototype% method closes the source iterator.
+info: >
+  Iterator Helpers proposal 2.1.6
+features: [iterator-helpers]
+---*/
+
+class TestIterator extends AsyncIterator {
+  async next() { 
+    return {done: false, value: 1};
+  }
+
+  closed = false;
+  async return(value) {
+    this.closed = true;
+    return {done: true, value};
+  }
+}
+
+async function* gen(x) { yield x; }
+
+const methods = [
+  iter => iter.map(x => x),
+  iter => iter.filter(x => x),
+  iter => iter.take(1),
+  iter => iter.drop(0),
+  iter => iter.asIndexedPairs(),
+  iter => iter.flatMap(gen),
+];
+
+for (const method of methods) {
+  const iter = new TestIterator();
+  const iterHelper = method(iter);
+
+  iterHelper.next().then(() => {
+    assertEq(iter.closed, false);
+    iterHelper.return(0).then(({done, value}) => {
+      assertEq(iter.closed, true);
+      assertEq(done, true);
+      assertEq(value, 0);
+    });
+  });
+}
+
+for (const method of methods) {
+  const iter = new TestIterator();
+  const iterHelper = method(iter);
+
+  assertEq(iter.closed, false);
+  iterHelper.return(0).then(({done, value}) => {
+    assertEq(iter.closed, true);
+    assertEq(done, true);
+    assertEq(value, 0);
+  });
+}
+
+if (typeof reportCompare == 'function')
+  reportCompare(0, 0);