From 1cdd6c3e698a6a4c28604448284993c4c20ca272 Mon Sep 17 00:00:00 2001
From: Steven Lambert <2433219+straker@users.noreply.github.com>
Date: Tue, 15 Oct 2024 10:27:11 -0600
Subject: [PATCH] fix(get-ancestry): add nth-child selector for multiple
 siblings of shadow root (#4606)

Closes: #4563
---
 lib/core/utils/get-ancestry.js  | 16 ++++++-----
 test/core/utils/get-ancestry.js | 49 +++++++++++++++++++++++----------
 2 files changed, 43 insertions(+), 22 deletions(-)

diff --git a/lib/core/utils/get-ancestry.js b/lib/core/utils/get-ancestry.js
index b80edb9338..f3ed38d272 100644
--- a/lib/core/utils/get-ancestry.js
+++ b/lib/core/utils/get-ancestry.js
@@ -2,22 +2,24 @@ import getShadowSelector from './get-shadow-selector';
 
 function generateAncestry(node) {
   const nodeName = node.nodeName.toLowerCase();
-  const parent = node.parentElement;
-  if (!parent) {
-    return nodeName;
-  }
+  const parentElement = node.parentElement;
+  const parentNode = node.parentNode;
 
   let nthChild = '';
   if (
     nodeName !== 'head' &&
     nodeName !== 'body' &&
-    parent.children.length > 1
+    parentNode.children.length > 1
   ) {
-    const index = Array.prototype.indexOf.call(parent.children, node) + 1;
+    const index = Array.prototype.indexOf.call(parentNode.children, node) + 1;
     nthChild = `:nth-child(${index})`;
   }
 
-  return generateAncestry(parent) + ' > ' + nodeName + nthChild;
+  if (!parentElement) {
+    return nodeName + nthChild;
+  }
+
+  return generateAncestry(parentElement) + ' > ' + nodeName + nthChild;
 }
 
 /**
diff --git a/test/core/utils/get-ancestry.js b/test/core/utils/get-ancestry.js
index c074f6f138..071853fb8d 100644
--- a/test/core/utils/get-ancestry.js
+++ b/test/core/utils/get-ancestry.js
@@ -1,50 +1,69 @@
-describe('axe.utils.getAncestry', function () {
+describe('axe.utils.getAncestry', () => {
   'use strict';
-  var fixture = document.getElementById('fixture');
-  var shadowTest = axe.testUtils.shadowSupport.v1 ? it : xit;
+  const fixture = document.getElementById('fixture');
 
-  afterEach(function () {
+  afterEach(() => {
     fixture.innerHTML = '';
   });
 
-  it('should be a function', function () {
+  it('should be a function', () => {
     assert.isFunction(axe.utils.getAncestry);
   });
 
-  it('should generate an ancestry selector', function () {
+  it('should generate an ancestry selector', () => {
     fixture.innerHTML = '<div>1</div> <p>2</p> <p>3</p>';
 
-    var sel1 = axe.utils.getAncestry(fixture.children[0]);
+    const sel1 = axe.utils.getAncestry(fixture.children[0]);
     assert.equal(sel1, 'html > body > div:nth-child(1) > div:nth-child(1)');
     assert.isNotNull(document.querySelector(sel1));
 
-    var sel2 = axe.utils.getAncestry(fixture.children[1]);
+    const sel2 = axe.utils.getAncestry(fixture.children[1]);
     assert.equal(sel2, 'html > body > div:nth-child(1) > p:nth-child(2)');
     assert.isNotNull(document.querySelector(sel1));
 
-    var sel3 = axe.utils.getAncestry(fixture.children[2]);
+    const sel3 = axe.utils.getAncestry(fixture.children[2]);
     assert.equal(sel3, 'html > body > div:nth-child(1) > p:nth-child(3)');
     assert.isNotNull(document.querySelector(sel1));
   });
 
-  shadowTest('generates selectors of nested shadow trees', function () {
-    var node = document.createElement('section');
+  it('generates selectors of nested shadow trees', () => {
+    const node = document.createElement('section');
     fixture.appendChild(node);
 
-    var shadowRoot1 = node.attachShadow({ mode: 'open' });
+    const shadowRoot1 = node.attachShadow({ mode: 'open' });
     shadowRoot1.innerHTML = '<div><article><slot /></article</div>';
 
-    var shadowRoot2 = shadowRoot1
+    const shadowRoot2 = shadowRoot1
       .querySelector('article')
       .attachShadow({ mode: 'open' });
     shadowRoot2.innerHTML = '<h1>Hello world</h1>';
 
-    var target = shadowRoot2.querySelector('h1');
-    var sel = axe.utils.getAncestry(target);
+    const target = shadowRoot2.querySelector('h1');
+    const sel = axe.utils.getAncestry(target);
     assert.deepEqual(sel, [
       'html > body > div:nth-child(1) > section',
       'div > article',
       'h1'
     ]);
   });
+
+  it('generates selectors of siblings in shadow tree', () => {
+    const node = document.createElement('section');
+    fixture.appendChild(node);
+
+    const shadowRoot = node.attachShadow({ mode: 'open' });
+    shadowRoot.innerHTML = '<div>1</div> <div>2</div>';
+
+    const sel1 = axe.utils.getAncestry(shadowRoot.children[0]);
+    assert.deepEqual(sel1, [
+      'html > body > div:nth-child(1) > section',
+      'div:nth-child(1)'
+    ]);
+
+    const sel2 = axe.utils.getAncestry(shadowRoot.children[1]);
+    assert.deepEqual(sel2, [
+      'html > body > div:nth-child(1) > section',
+      'div:nth-child(2)'
+    ]);
+  });
 });