From 38cad9451dbde52fbab0835e3c1673825c57e5b7 Mon Sep 17 00:00:00 2001
From: Wilco Fiers <WilcoFiers@users.noreply.github.com>
Date: Thu, 1 Apr 2021 10:41:15 +0200
Subject: [PATCH] fix(respondable): work on iframes in shadow DOM (#2857)

---
 lib/core/utils/respondable/assert-window.js |  8 ++--
 test/core/utils/respondable.js              | 47 ++++++++++++++++++++-
 2 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/lib/core/utils/respondable/assert-window.js b/lib/core/utils/respondable/assert-window.js
index 8e767d0d51..46f37d9659 100644
--- a/lib/core/utils/respondable/assert-window.js
+++ b/lib/core/utils/respondable/assert-window.js
@@ -10,10 +10,10 @@ export function assertIsParentWindow(win) {
 
 export function assertIsFrameWindow(win) {
   assetNotGlobalWindow(win);
-  const frames = Array.from(window.frames);
-  if (!frames.some(frame => frame === win)) {
-    throw new Error('Respondable target must be a frame in the current window');
-  }
+  assert(
+    win.parent === window,
+    'Respondable target must be a frame in the current window'
+  );
 }
 
 export function assetNotGlobalWindow(win) {
diff --git a/test/core/utils/respondable.js b/test/core/utils/respondable.js
index 12fecdf41e..a016a6bc8c 100644
--- a/test/core/utils/respondable.js
+++ b/test/core/utils/respondable.js
@@ -31,6 +31,7 @@ describe('axe.utils.respondable', function() {
   var postMessage = window.postMessage;
   var captureError = axe.testUtils.captureError;
   var isIE11 = axe.testUtils.isIE11;
+  var shadowSupported = axe.testUtils.shadowSupport.v1;
   this.timeout(1000);
 
   beforeEach(function(done) {
@@ -151,6 +152,37 @@ describe('axe.utils.respondable', function() {
       );
     });
 
+    (shadowSupported ? it : xit)('works with frames in shadow DOM', function(
+      done
+    ) {
+      fixture.innerHTML = '<div id="shadow-root"></div>';
+      var shadowRoot = fixture
+        .querySelector('#shadow-root')
+        .attachShadow({ mode: 'open' });
+      frame = document.createElement('iframe');
+      frame.src = '../mock/frames/test.html';
+
+      frame.addEventListener('load', function() {
+        var called = false;
+        frameWin = frame.contentWindow;
+        frameSubscribe = frameWin.axe.utils.respondable.subscribe;
+
+        frameSubscribe('greeting', function(msg) {
+          assert.equal(msg, 'hello');
+          called = true;
+        });
+        respondable(frameWin, 'greeting', 'hello');
+        afterMessage(
+          frameWin,
+          captureError(function() {
+            assert.isTrue(called);
+            done();
+          }, done)
+        );
+      });
+      shadowRoot.appendChild(frame);
+    });
+
     it('is not called on a different topic', function(done) {
       var called = false;
       frameSubscribe('otherTopic', function() {
@@ -226,6 +258,17 @@ describe('axe.utils.respondable', function() {
       respondable(frameWin, 'greeting', new Error('expected message'));
     });
 
+    (isIE11 ? it.skip : it)(
+      // In IE win.parent is read-only
+      'throws if frame.parent is not the window',
+      function() {
+        frameWin.parent = frameWin;
+        assert.throws(function() {
+          respondable(frameWin, 'greeting');
+        });
+      }
+    );
+
     (isIE11 ? it.skip : it)(
       // In IE win.parent is read-only
       'is not called when the source is not a frame in the page',
@@ -239,8 +282,10 @@ describe('axe.utils.respondable', function() {
         frameSubscribe('greeting', function() {
           doneOnce(new Error('subscribe should not be called'));
         });
-        frameWin.parent = frameWin;
         respondable(frameWin, 'greeting');
+        // Swap parent after the message is sent, but before it is received:
+        frameWin.parent = frameWin;
+
         setTimeout(
           captureError(function() {
             assert.isTrue(called);