diff --git a/resources/testdriver.js b/resources/testdriver.js
index e7df7ede41eb97..b0355af84a9418 100644
--- a/resources/testdriver.js
+++ b/resources/testdriver.js
@@ -1194,6 +1194,32 @@
             return role;
         },
 
+        /**
+         * Get accessibility properties for an element.
+         *
+         * @param {Element} element
+         * @returns {Promise} fulfilled after the accessibility properties are
+         *                    returned, or rejected in the cases the WebDriver
+         *                    command errors
+         */
+        get_element_accessible_node: async function(element) {
+            let acc = await window.test_driver_internal.get_element_accessible_node(element);
+            return acc;
+        },
+
+        /**
+         * Get properties for an accessible node.
+         *
+         * @param {String} id
+         * @returns {Promise} fulfilled after the accessibility properties are
+         *                    returned, or rejected in the cases the WebDriver
+         *                    command errors
+         */
+        get_accessible_node: async function(accId) {
+            let acc = await window.test_driver_internal.get_accessible_node(accId);
+            return acc;
+        },
+
         /**
          * Send keys to an element.
          *
@@ -2370,6 +2396,14 @@
             throw new Error("get_computed_name is a testdriver.js function which cannot be run in this context.");
         },
 
+        async get_element_accessible_node(element) {
+            throw new Error("get_element_accessible_node is a testdriver.js function which cannot be run in this context.");
+        },
+
+        async get_accessible_node(accId) {
+            throw new Error("get_accessible_node is a testdriver.js function which cannot be run in this context.");
+        },
+
         async send_keys(element, keys) {
             if (this.in_automation) {
                 throw new Error("send_keys() is not implemented by testdriver-vendor.js");
diff --git a/tools/wptrunner/wptrunner/executors/actions.py b/tools/wptrunner/wptrunner/executors/actions.py
index 785962062822bf..0b1c76759a3ba3 100644
--- a/tools/wptrunner/wptrunner/executors/actions.py
+++ b/tools/wptrunner/wptrunner/executors/actions.py
@@ -26,6 +26,19 @@ def __call__(self, payload):
         self.protocol.cookies.delete_all_cookies()
 
 
+class GetAccessibleNodeAction:
+    name = "get_accessible_node"
+
+    def __init__(self, logger, protocol):
+        self.logger = logger
+        self.protocol = protocol
+
+    def __call__(self, payload):
+        id = payload["accId"]
+        self.logger.debug("Getting accessible node: %s" % id)
+        return self.protocol.accessibility.get_accessible_node(id)
+
+
 class GetAllCookiesAction:
     name = "get_all_cookies"
 
@@ -66,6 +79,20 @@ def __call__(self, payload):
         return self.protocol.accessibility.get_computed_role(element)
 
 
+class GetElementAccessibleNodeAction:
+    name = "get_element_accessible_node"
+
+    def __init__(self, logger, protocol):
+        self.logger = logger
+        self.protocol = protocol
+
+    def __call__(self, payload):
+        selector = payload["selector"]
+        element = self.protocol.select.element_by_selector(selector)
+        self.logger.debug("Getting accessible node for element: %s" % element)
+        return self.protocol.accessibility.get_element_accessible_node(element)
+
+
 class GetNamedCookieAction:
     name = "get_named_cookie"
 
@@ -600,6 +627,8 @@ def __call__(self, payload):
            GetNamedCookieAction,
            GetComputedLabelAction,
            GetComputedRoleAction,
+           GetElementAccessibleNodeAction,
+           GetAccessibleNodeAction,
            SendKeysAction,
            MinimizeWindowAction,
            SetWindowRectAction,
diff --git a/tools/wptrunner/wptrunner/executors/executormarionette.py b/tools/wptrunner/wptrunner/executors/executormarionette.py
index 37ec11553773e5..4bce6673ed24f4 100644
--- a/tools/wptrunner/wptrunner/executors/executormarionette.py
+++ b/tools/wptrunner/wptrunner/executors/executormarionette.py
@@ -731,6 +731,12 @@ def get_computed_label(self, element):
     def get_computed_role(self, element):
         return element.computed_role
 
+    def get_element_accessible_node(self, element):
+        return element.accessible_node
+
+    def get_accessible_node(self, id):
+        return self.marionette.get_accessible_node(id)
+
 
 class MarionetteVirtualSensorProtocolPart(VirtualSensorProtocolPart):
     def setup(self):
diff --git a/tools/wptrunner/wptrunner/executors/protocol.py b/tools/wptrunner/wptrunner/executors/protocol.py
index d5f9b0bfc4bb89..e5134175eb52b4 100644
--- a/tools/wptrunner/wptrunner/executors/protocol.py
+++ b/tools/wptrunner/wptrunner/executors/protocol.py
@@ -335,6 +335,18 @@ def get_computed_role(self, element):
         :param element: A protocol-specific handle to an element."""
         pass
 
+    def get_element_accessible_node(self, element):
+        """Return the accessibility properties for a specific element.
+
+        :param element: A protocol-specific handle to an element."""
+        pass
+
+    def get_accessible_node(self, id):
+        """Return the properties for a specific accessible node.
+
+        :param id: The id of the accessible node."""
+        pass
+
 
 class WebExtensionsProtocolPart(ProtocolPart):
     """Protocol part for managing WebExtensions"""
diff --git a/tools/wptrunner/wptrunner/testdriver-extra.js b/tools/wptrunner/wptrunner/testdriver-extra.js
index 925cc6b1d27826..2efeb556b22556 100644
--- a/tools/wptrunner/wptrunner/testdriver-extra.js
+++ b/tools/wptrunner/wptrunner/testdriver-extra.js
@@ -495,6 +495,16 @@
         return create_context_action("get_computed_role", context, {selector});
     };
 
+    window.test_driver_internal.get_element_accessible_node = function(element) {
+        const selector = get_selector(element);
+        const context = get_context(element);
+        return create_context_action("get_element_accessible_node", context, {selector});
+    };
+
+    window.test_driver_internal.get_accessible_node = function(accId, context=null) {
+        return create_context_action("get_accessible_node", context, { accId });
+    };
+
     window.test_driver_internal.get_named_cookie = function(name, context=null) {
         return create_context_action("get_named_cookie", context, {name});
     };
diff --git a/wai-aria/scripts/aria-utils.js b/wai-aria/scripts/aria-utils.js
index bf86dd051c30f6..45961a97243d7c 100644
--- a/wai-aria/scripts/aria-utils.js
+++ b/wai-aria/scripts/aria-utils.js
@@ -192,5 +192,63 @@ const AriaUtils = {
     this.verifyLabelsBySelector(".ex-label-only", labelTestNamePrefix);
     this.verifyRolesBySelector(".ex-role-only", roleTestNamePrefix);
   },
-};
 
+
+  /*
+  Asserts that the tree for a given accessible node matches the specified tree
+  structure.
+  This takes an accessible node and is not wrapped in a test. Most test files
+  will want to use verifyAccessibilityTree instead.
+  For example:
+  <div id="listbox" role="listbox" aria-label="listbox">
+    <div id="option1" role="option" aria-label="option1"></div>
+    <div id="option2" role="option" aria-label="option2"></div>
+  </div>
+  ...
+  const listbox = await test_driver.get_element_accessible_node(document.getElementById("listbox"));
+  await AriaUtils.assertAccessibilityTree(listbox, {
+    role: "listbox",
+    label: "listbox",
+    children: [
+      { role: "option", label: "option1", children: [] },
+      { role: "option", label: "option2", children: [] },
+    ],
+  }, "#listbox");
+  */
+  assertAccessibilityTree: async function(acc, tree, position) {
+    for (const key in tree) {
+      if (key == "children") {
+        assert_equals(acc.children.length, tree.children.length, `${position} children.length`);
+        for (let c = 0; c < acc.children.length; ++c) {
+          const childId = acc.children[c];
+          const childAcc = await test_driver.get_accessible_node(childId);
+          await AriaUtils.assertAccessibilityTree(childAcc, tree.children[c], `${position}[${c}]`);
+        }
+        continue;
+      }
+      assert_equals(acc[key], tree[key], `${position} ${key}`);
+    }
+  },
+
+
+  /*
+  Verifies that the tree for a given accessible node matches the specified tree
+  structure.
+  This calls assertAccessibilityTree, but it accepts a CSS selector and wraps
+  the call in promise_test.
+  For example:
+  <div id="listbox"> ... </div>
+  ...
+  AriaUtils.verifyAccessibilityTree("#listbox", { ... });
+  */
+  verifyAccessibilityTree: function(selector, tree) {
+    const el = document.querySelector(selector);
+    if (!el) {
+      throw `selector passed to verifyAccessibilityTree("${selector}") doesn't match an element`;
+    }
+    promise_test(async t => {
+      const acc = await test_driver.get_element_accessible_node(el);
+      await AriaUtils.assertAccessibilityTree(acc, tree, selector);
+    }, `accessibility tree for ${selector}`);
+  },
+};
diff --git a/wai-aria/state/basic.tentative.html b/wai-aria/state/basic.tentative.html
new file mode 100644
index 00000000000000..91c9583b102284
--- /dev/null
+++ b/wai-aria/state/basic.tentative.html
@@ -0,0 +1,59 @@
+<!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>
+
+<div id="checkboxCheckedMissing" role="checkbox"></div>
+<div id="checkboxCheckedTrue" role="checkbox" aria-checked="true"></div>
+<div id="checkboxCheckedFalse" role="checkbox" aria-checked="false"></div>
+<div id="checkboxCheckedMixed" role="checkbox" aria-checked="mixed"></div>
+<div id="buttonPressedMissing" role="button"></div>
+<div id="buttonPressedTrue" role="button" aria-pressed="true"></div>
+<div id="buttonPressedFalse" role="button" aria-pressed="false"></div>
+<div id="buttonPressedMixed" role="button" aria-pressed="mixed"></div>
+
+<script>
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("checkboxCheckedMissing"));
+  assert_equals(acc.checked, "false");
+}, "checkbox with missing aria-checked");
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("checkboxCheckedTrue"));
+  assert_equals(acc.checked, "true");
+}, "checkbox with aria-checked true");
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("checkboxCheckedFalse"));
+  assert_equals(acc.checked, "false");
+}, "checkbox with aria-checked false");
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("checkboxCheckedMixed"));
+  assert_equals(acc.checked, "mixed");
+}, "checkbox with aria-checked mixed");
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("buttonPressedMissing"));
+  assert_equals(acc.pressed, "undefined");
+}, "button with missing aria-pressed");
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("buttonPressedTrue"));
+  assert_equals(acc.pressed, "true");
+}, "button with aria-pressed true");
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("buttonPressedFalse"));
+  assert_equals(acc.pressed, "false");
+}, "button with aria-pressed false");
+
+promise_test(async t => {
+  const acc = await test_driver.get_element_accessible_node(document.getElementById("buttonPressedMixed"));
+  assert_equals(acc.pressed, "mixed");
+}, "button with aria-pressed mixed");
+
+</script>
diff --git a/wai-aria/tree/basic.tentative.html b/wai-aria/tree/basic.tentative.html
new file mode 100644
index 00000000000000..67ac81d91228b5
--- /dev/null
+++ b/wai-aria/tree/basic.tentative.html
@@ -0,0 +1,39 @@
+<!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="listbox" role="listbox" aria-label="listbox">
+  <div id="option1" role="option" aria-label="option1"></div>
+  <div id="option2" role="option" aria-label="option2"></div>
+</div>
+
+<script>
+
+promise_test(async t => {
+  const listbox = await test_driver.get_element_accessible_node(document.getElementById("listbox"));
+  assert_equals(listbox.children.length, 2);
+  const option1 = await test_driver.get_accessible_node(listbox.children[0]);
+  assert_equals(option1.id, listbox.children[0]);
+  assert_equals(option1.parent, listbox.id);
+  assert_equals(option1.role, "option");
+  assert_equals(option1.label, "option1");
+  const option2 = await test_driver.get_accessible_node(listbox.children[1]);
+  assert_equals(option2.id, listbox.children[1]);
+  assert_equals(option2.parent, listbox.id);
+  assert_equals(option2.label, "option2");
+}, "listbox explicit tree");
+
+AriaUtils.verifyAccessibilityTree("#listbox", {
+  role: "listbox",
+  label: "listbox",
+  children: [
+    { role: "option", label: "option1", children: [] },
+    { role: "option", label: "option2", children: [] },
+  ],
+});
+
+</script>