1 files changed, 57 insertions, 0 deletions
diff --git a/js/src/tests/non262/AsyncIterator/prototype/lazy-methods-iterator-not-closed-on-next-then-throws.js b/js/src/tests/non262/AsyncIterator/prototype/lazy-methods-iterator-not-closed-on-next-then-throws.js
new file mode 100644
index 0000000000..609a49c3c7
--- /dev/null
+++ b/js/src/tests/non262/AsyncIterator/prototype/lazy-methods-iterator-not-closed-on-next-then-throws.js
@@ -0,0 +1,57 @@
+// |reftest| skip-if(!this.hasOwnProperty('AsyncIterator'))
+
+//
+//
+/*---
+esid: pending
+description: Lazy %AsyncIterator.prototype% methods don't close the iterator if `then` returned by `next` throws.
+info: >
+    AsyncIterator Helpers proposal 2.1.6
+features: [iterator-helpers]
+---*/
+
+class TestError extends Error {}
+
+class TestIterator extends AsyncIterator {
+  next() {
+    return {
+      then() {
+        throw new TestError();
+      }
+    };
+  }
+
+  closed = false;
+  async return(value) {
+    this.closed = true;
+    return {done: true, value};
+  }
+}
+
+const methods = [
+  ["map", x => x],
+  ["filter", x => true],
+  ["take", Infinity],
+  ["drop", 0],
+  ["asIndexedPairs", undefined],
+  ["flatMap", async function*(x) { yield x; }],
+];
+
+(async () => {
+  for (const [method, arg] of methods) {
+    const iterator = new TestIterator();
+    assertEq(iterator.closed, false);
+
+    try {
+      await iterator[method](arg).next();
+      assertEq(true, false, 'Expected exception');
+    } catch(err) {
+      console.log(err);
+      assertEq(err instanceof TestError, true);
+    }
+    assertEq(iterator.closed, false);
+  }
+})();
+
+if (typeof reportCompare == 'function')
+  reportCompare(0, 0);