1 files changed, 67 insertions, 0 deletions
diff --git a/js/src/tests/ecma_6/Promise/promise-subclassing.js b/js/src/tests/ecma_6/Promise/promise-subclassing.js
new file mode 100644
index 000000000..eba15a1d6
--- /dev/null
+++ b/js/src/tests/ecma_6/Promise/promise-subclassing.js
@@ -0,0 +1,67 @@
+// |reftest| skip-if(!xulRuntime.shell) -- needs drainJobQueue
+
+if (!this.Promise) {
+    this.reportCompare && reportCompare(true,true);
+    quit(0);
+}
+
+let results = [];
+
+class SubPromise extends Promise {
+  constructor(executor) {
+    results.push('SubPromise ctor called');
+    super(executor);
+  }
+  then(res, rej) {
+    results.push('SubPromise#then called');
+    return intermediatePromise = super.then(res, rej);
+  }
+}
+
+let subPromise = new SubPromise(function(res, rej) {
+  results.push('SubPromise ctor called executor');
+  res('result');
+});
+
+let intermediatePromise;
+let allSubPromise = SubPromise.all([subPromise]);
+
+assertEq(subPromise instanceof SubPromise, true);
+assertEq(allSubPromise instanceof SubPromise, true);
+assertEq(intermediatePromise instanceof SubPromise, true);
+
+expected = [
+'SubPromise ctor called',
+'SubPromise ctor called executor',
+'SubPromise ctor called',
+'SubPromise#then called',
+'SubPromise ctor called',
+];
+
+assertEq(results.length, expected.length);
+expected.forEach((expected,i) => assertEq(results[i], expected));
+
+subPromise.then(val=>results.push('subPromise.then with val ' + val));
+allSubPromise.then(val=>results.push('allSubPromise.then with val ' + val));
+
+expected.forEach((expected,i) => assertEq(results[i], expected));
+expected = expected.concat([
+'SubPromise#then called',
+'SubPromise ctor called',
+'SubPromise#then called',
+'SubPromise ctor called',
+]);
+
+assertEq(results.length, expected.length);
+expected.forEach((expected,i) => assertEq(results[i], expected));
+
+drainJobQueue();
+
+expected = expected.concat([
+'subPromise.then with val result',
+'allSubPromise.then with val result',
+]);
+
+assertEq(results.length, expected.length);
+
+this.reportCompare && reportCompare(0, 0, "ok");