1 files changed, 40 insertions, 0 deletions
diff --git a/js/src/tests/ecma_6/Generators/delegating-yield-3.js b/js/src/tests/ecma_6/Generators/delegating-yield-3.js
new file mode 100644
index 000000000..34800f1b0
--- /dev/null
+++ b/js/src/tests/ecma_6/Generators/delegating-yield-3.js
@@ -0,0 +1,40 @@
+// Test yield* with iter.next and monkeypatching.
+
+function* g(n) { for (var i=0; i<n; i++) yield i; }
+function* delegate(iter) { return yield* iter; }
+var GeneratorObjectPrototype = Object.getPrototypeOf(g).prototype;
+var GeneratorObjectPrototype_next = GeneratorObjectPrototype.next;
+
+// Monkeypatch next on an iterator.
+var inner = g(20);
+var outer = delegate(inner);
+assertIteratorNext(outer, 0);
+assertIteratorNext(outer, 1);
+inner.next = function() { return { patched: true }; };
+// 42 yielded directly without re-boxing.
+assertEq(true, outer.next().patched);
+// Outer generator not terminated.
+assertEq(true, outer.next().patched);
+// Restore.
+inner.next = GeneratorObjectPrototype_next;
+assertIteratorNext(outer, 2);
+// Repatch.
+inner.next = function() { return { value: 42, done: true }; };
+assertIteratorDone(outer, 42);
+
+// Monkeypunch next on the prototype.
+var inner = g(20);
+var outer = delegate(inner);
+assertIteratorNext(outer, 0);
+assertIteratorNext(outer, 1);
+GeneratorObjectPrototype.next = function() { return { patched: true }; };
+// 42 yielded directly without re-boxing.
+assertEq(true, GeneratorObjectPrototype_next.call(outer).patched);
+// Outer generator not terminated.
+assertEq(true, GeneratorObjectPrototype_next.call(outer).patched);
+// Restore.
+GeneratorObjectPrototype.next = GeneratorObjectPrototype_next;
+assertIteratorNext(outer, 2);
+
+if (typeof reportCompare == "function")
+    reportCompare(true, true);