From 5bb75878a62a622e5d7bf70176a359ca50f99500 Mon Sep 17 00:00:00 2001
From: theohale <5333778+HaTheo@users.noreply.github.com>
Date: Mon, 8 Jun 2026 15:42:00 -0400
Subject: [PATCH 1/2] Add initial implementation of tree structure with
 accessibility verification as per issue #2091

---
 wai-aria/subtree/treeitems.tentative.html | 42 +++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 wai-aria/subtree/treeitems.tentative.html
diff --git a/wai-aria/subtree/treeitems.tentative.html b/wai-aria/subtree/treeitems.tentative.html
new file mode 100644
index 00000000000000..9c5899ae553330
--- /dev/null
+++ b/wai-aria/subtree/treeitems.tentative.html
@@ -0,0 +1,42 @@
+<!doctype html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/wai-aria/scripts/aria-utils.js"></script>
+
+<div id="tree" role="tree">
+  <div role="treeitem" aria-level="1">Fruits</div>
+  <div role="treeitem" aria-level="2">Apples</div>
+  <div role="treeitem" aria-level="2">Pears</div>
+  <div role="treeitem" aria-level="2">Oranges</div>
+  <div role="treeitem" aria-level="1">Vegetables</div>
+  <div role="treeitem" aria-level="2">Carrots</div>
+  <div role="treeitem" aria-level="2">Broccoli</div>
+  <div role="treeitem" aria-level="2">Spinach</div>
+</div>
+
+<script>
+
+AriaUtils.verifyAccessibilitySubtree("#tree", {
+  role: "tree",
+  children: [
+    { role: "treeitem", label: "Fruits", level: 1,
+      children: [
+        { role: "treeitem", label: "Apples", level: 2, children: [] },
+        { role: "treeitem", label: "Pears", level: 2, children: [] },
+        { role: "treeitem", label: "Oranges", level: 2, children: [] },
+      ],
+    },
+    { role: "treeitem", label: "Vegetables", level: 1,
+      children: [
+        { role: "treeitem", label: "Carrots", level: 2, children: [] },
+        { role: "treeitem", label: "Broccoli", level: 2, children: [] },
+        { role: "treeitem", label: "Spinach", level: 2, children: [] },
+      ],
+    },
+  ],
+});
+
+</script>

From 804f776987384140bafef02773558561a1aa1534 Mon Sep 17 00:00:00 2001
From: theohale <5333778+HaTheo@users.noreply.github.com>
Date: Tue, 9 Jun 2026 15:24:53 -0400
Subject: [PATCH 2/2] adding aria-posinset and aria-setsize per requirement.

---
 wai-aria/subtree/treeitems.tentative.html | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/wai-aria/subtree/treeitems.tentative.html b/wai-aria/subtree/treeitems.tentative.html
index 9c5899ae553330..8ad6d2cae91aa6 100644
--- a/wai-aria/subtree/treeitems.tentative.html
+++ b/wai-aria/subtree/treeitems.tentative.html
@@ -7,14 +7,14 @@
 <script src="/wai-aria/scripts/aria-utils.js"></script>
 
 <div id="tree" role="tree">
-  <div role="treeitem" aria-level="1">Fruits</div>
-  <div role="treeitem" aria-level="2">Apples</div>
-  <div role="treeitem" aria-level="2">Pears</div>
-  <div role="treeitem" aria-level="2">Oranges</div>
-  <div role="treeitem" aria-level="1">Vegetables</div>
-  <div role="treeitem" aria-level="2">Carrots</div>
-  <div role="treeitem" aria-level="2">Broccoli</div>
-  <div role="treeitem" aria-level="2">Spinach</div>
+  <div role="treeitem" aria-level="1" aria-posinset="1" aria-setsize="2">Fruits</div>
+  <div role="treeitem" aria-level="2" aria-posinset="1" aria-setsize="3">Apples</div>
+  <div role="treeitem" aria-level="2" aria-posinset="2" aria-setsize="3">Pears</div>
+  <div role="treeitem" aria-level="2" aria-posinset="3" aria-setsize="3">Oranges</div>
+  <div role="treeitem" aria-level="1" aria-posinset="2" aria-setsize="2">Vegetables</div>
+  <div role="treeitem" aria-level="2" aria-posinset="1" aria-setsize="3">Carrots</div>
+  <div role="treeitem" aria-level="2" aria-posinset="2" aria-setsize="3">Broccoli</div>
+  <div role="treeitem" aria-level="2" aria-posinset="3" aria-setsize="3">Spinach</div>
 </div>
 
 <script>
