basic root accessibility stuff

src/accessibility.ts

@@ -55,13 +55,12 @@ export interface AXNode {
     isLeafNode(): boolean;
     isControl(): boolean;
     serialize(): SerializedAXNode;
-    findElement(element: dom.ElementHandle): Promise<AXNode|null>;
     children(): Iterable<AXNode>;
 }
 
 export class Accessibility {
-  private _getAXTree:  () => Promise<AXNode>;
-  constructor(getAXTree: () => Promise<AXNode>) {
+  private _getAXTree:  (needle?: dom.ElementHandle) => Promise<{tree: AXNode, needle?: AXNode}>;
+  constructor(getAXTree: (needle?: dom.ElementHandle) => Promise<{tree: AXNode, needle?: AXNode}>) {
     this._getAXTree = getAXTree;
   }
 
@@ -73,18 +72,12 @@ export class Accessibility {
       interestingOnly = true,
       root = null,
     } = options;
-    const defaultRoot = await this._getAXTree();
-    let needle: AXNode | null = defaultRoot;
-    if (root) {
-      needle = await defaultRoot.findElement(root);
-      if (!needle)
-        return null;
-    }
+    const {tree, needle} = await this._getAXTree(root);
     if (!interestingOnly)
       return serializeTree(needle)[0];
 
     const interestingNodes: Set<AXNode> = new Set();
-    collectInterestingNodes(interestingNodes, defaultRoot, false);
+    collectInterestingNodes(interestingNodes, tree, false);
     if (root && !interestingNodes.has(needle))
       return null;
     return serializeTree(needle, interestingNodes)[0];

src/chromium/crAccessibility.ts

@@ -20,9 +20,13 @@ import { Protocol } from './protocol';
 import * as dom from '../dom';
 import * as accessibility from '../accessibility';
 
-export async function getAccessibilityTree(client: CRSession) : Promise<accessibility.AXNode> {
+export async function getAccessibilityTree(client: CRSession, needle?: dom.ElementHandle) : Promise<{tree: accessibility.AXNode, needle?: accessibility.AXNode}> {
   const {nodes} = await client.send('Accessibility.getFullAXTree');
-  return CRAXNode.createTree(client, nodes);
+  const tree = CRAXNode.createTree(client, nodes);
+  return {
+    tree,
+    needle: needle && await tree._findElement(needle)
+  };
 }
 
 class CRAXNode implements accessibility.AXNode {
@@ -90,7 +94,7 @@ class CRAXNode implements accessibility.AXNode {
     return this._children;
   }
 
-  async findElement(element: dom.ElementHandle): Promise<CRAXNode | null> {
+  async _findElement(element: dom.ElementHandle): Promise<CRAXNode | null> {
     const remoteObject = element._remoteObject as Protocol.Runtime.RemoteObject;
     const {node: {backendNodeId}} = await this._client.send('DOM.describeNode', {objectId: remoteObject.objectId});
     const needle = this.find(node => node._payload.backendDOMNodeId === backendNodeId);

src/chromium/crPage.ts

@@ -480,8 +480,8 @@ export class CRPage implements PageDelegate {
     return to._createHandle(result.object).asElement()!;
   }
 
-  async getAccessibilityTree(): Promise<accessibility.AXNode> {
-    return getAccessibilityTree(this._client);
+  async getAccessibilityTree(needle?: dom.ElementHandle) {
+    return getAccessibilityTree(this._client, needle);
   }
 
   async pdf(options?: types.PDFOptions): Promise<platform.BufferType> {

src/firefox/ffAccessibility.ts

@@ -18,15 +18,21 @@
 import * as accessibility from '../accessibility';
 import { FFSession } from './ffConnection';
 import { Protocol } from './protocol';
+import * as dom from '../dom';
 
-export async function getAccessibilityTree(session: FFSession) : Promise<accessibility.AXNode> {
-  const { tree } = await session.send('Accessibility.getFullAXTree');
-  return new FFAXNode(tree);
+export async function getAccessibilityTree(session: FFSession, needle: dom.ElementHandle) : Promise<{tree: accessibility.AXNode, needle?: accessibility.AXNode}> {
+  const objectId = needle ? needle._remoteObject.objectId : undefined;
+  const { tree } = await session.send('Accessibility.getFullAXTree', { objectId });
+  const axNode = new FFAXNode(tree);
+  return {
+    tree: axNode,
+    needle: needle && axNode._findNeedle()
+  };
 }
 
 class FFAXNode implements accessibility.AXNode {
   _children: FFAXNode[];
-  private _payload: any;
+  private _payload: Protocol.AXTree;
   private _editable: boolean;
   private _richlyEditable: boolean;
   private _focusable: boolean;
@@ -77,8 +83,15 @@ class FFAXNode implements accessibility.AXNode {
     return this._children;
   }
 
-  async findElement(): Promise<FFAXNode | null> {
-    throw new Error('Not implimented');
+  _findNeedle(): FFAXNode | null {
+    if (this._payload.foundObject)
+      return this;
+    for (const child of this._children) {
+      const found = child._findNeedle();
+      if (found)
+        return found;
+    }
+    return null;
   }
 
   isLeafNode(): boolean {

src/firefox/ffPage.ts

@@ -355,8 +355,8 @@ export class FFPage implements PageDelegate {
     return handle;
   }
 
-  async getAccessibilityTree() : Promise<accessibility.AXNode> {
-    return getAccessibilityTree(this._session);
+  async getAccessibilityTree(needle?: dom.ElementHandle) {
+    return getAccessibilityTree(this._session, needle);
   }
 
   coverage(): Coverage | undefined {

src/page.ts

@@ -68,7 +68,7 @@ export interface PageDelegate {
   setInputFiles(handle: dom.ElementHandle<HTMLInputElement>, files: types.FilePayload[]): Promise<void>;
   getBoundingBox(handle: dom.ElementHandle): Promise<types.Rect | null>;
 
-  getAccessibilityTree(): Promise<accessibility.AXNode>;
+  getAccessibilityTree(needle?: dom.ElementHandle): Promise<{tree: accessibility.AXNode, needle?: accessibility.AXNode}>;
   pdf?: (options?: types.PDFOptions) => Promise<platform.BufferType>;
   coverage(): Coverage | undefined;
 }

src/webkit/wkAccessibility.ts

@@ -16,10 +16,16 @@
 import * as accessibility from '../accessibility';
 import { WKSession } from './wkConnection';
 import { Protocol } from './protocol';
+import * as dom from '../dom';
 
-export async function getAccessibilityTree(session: WKSession) {
-  const {axNode} = await session.send('Page.accessibilitySnapshot');
-  return new WKAXNode(axNode);
+export async function getAccessibilityTree(session: WKSession, needle?: dom.ElementHandle) {
+  const objectId = needle ? needle._remoteObject.objectId : undefined;
+  const {axNode} = await session.send('Page.accessibilitySnapshot', { objectId });
+  const tree = new WKAXNode(axNode);
+  return {
+    tree,
+    needle: needle && tree._findNeedle()
+  };
 }
 
 class WKAXNode implements accessibility.AXNode {
@@ -38,7 +44,14 @@ class WKAXNode implements accessibility.AXNode {
       return this._children;
     }
 
-    async findElement() {
+    _findNeedle() : WKAXNode {
+      if (this._payload.found)
+        return this;
+      for (const child of this._children) {
+        const found = child._findNeedle()
+        if (found)
+          return found;
+      }
       return null;
     }
 

src/webkit/wkPage.ts

@@ -497,8 +497,8 @@ export class WKPage implements PageDelegate {
     return to._createHandle(result.object) as dom.ElementHandle<T>;
   }
 
-  async getAccessibilityTree() : Promise<accessibility.AXNode> {
-    return getAccessibilityTree(this._session);
+  async getAccessibilityTree(needle?: dom.ElementHandle) : Promise<{tree: accessibility.AXNode, needle?: accessibility.AXNode}> {
+    return getAccessibilityTree(this._session, needle);
   }
 
   coverage(): Coverage | undefined {

test/accessibility.spec.js

@@ -363,8 +363,8 @@ module.exports.describe = function({testRunner, expect, FFOX, CHROMIUM, WEBKIT})
         expect(snapshot.children[0]).toEqual(golden);
       });
 
-      describe.skip(FFOX || WEBKIT)('root option', function() {
-        it('should work a button', async({page}) => {
+      describe('root option', function() {
+        fit('should work a button', async({page}) => {
           await page.setContent(`<button>My Button</button>`);
 
           const button = await page.$('button');