WIP: core(axe): new audits empty-table-header, frame-focusable-content

lighthouse-cli/test/cli/__snapshots__/index-test.js.snap

@@ -255,9 +255,15 @@ Object {
     Object {
       "path": "accessibility/duplicate-id-aria",
     },
+    Object {
+      "path": "accessibility/empty-table-header",
+    },
     Object {
       "path": "accessibility/form-field-multiple-labels",
     },
+    Object {
+      "path": "accessibility/frame-focusable-content",
+    },
     Object {
       "path": "accessibility/frame-title",
     },
@@ -588,11 +594,21 @@ Object {
           "id": "duplicate-id-aria",
           "weight": 10,
         },
+        Object {
+          "group": "a11y-tables-lists",
+          "id": "empty-table-header",
+          "weight": 2,
+        },
         Object {
           "group": "a11y-names-labels",
           "id": "form-field-multiple-labels",
           "weight": 2,
         },
+        Object {
+          "group": "a11y-navigation",
+          "id": "frame-focusable-content",
+          "weight": 3,
+        },
         Object {
           "group": "a11y-names-labels",
           "id": "frame-title",

lighthouse-cli/test/fixtures/a11y/a11y_tester.html

@@ -135,12 +135,24 @@
       <div id="duplicate-id-aria"></div>
       <input type="text" aria-labelledby="duplicate-id-aria"/>
     </section>
+    <p>empty-table-header</p>
+    <section>
+      <table>
+        <tr>
+          <th></th>
+        </tr>
+      </table>
+    </section>
     <p>form-field-multiple-labels</p>
     <section>
       <label for="form-field-multiple-labels" id="label1">label1</label>
       <label for="form-field-multiple-labels">label2</label>
       <input type="checkbox" id="form-field-multiple-labels" />
     </section>
+    <p>frame-focusable-content</p>
+    <section>
+      <iframe title="some title" tabindex="-1" src="../dobetterweb/focusable-iframe.html"></iframe>
+    </section>
     <p>frame-title</p>
     <section>
       <iframe id="frame-title"></iframe>

lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html

@@ -227,6 +227,15 @@ <h2>Do better web tester page</h2>
 <button class="small-button">Do something</button>
 <button class="small-button">Do something else</button>
 
+<!-- FAIL - frame-focusable-content -->
+<iframe tabindex="-1" src="focusable-iframe.html"></iframe>
+<!-- FAIL - empty-table-header -->
+<table>
+  <tr>
+    <th></th>
+  </tr>
+</table>
+
 <!-- Some websites overwrite the original Error object. The captureJSCallUsage function
   relies on the native Error object and prepareStackTrace from V8. When overwriting the stack
   property the e.stack inside the gatherer won't be in the correct format

lighthouse-cli/test/fixtures/dobetterweb/focusable-iframe.html

@@ -0,0 +1 @@
+<a href='/'>Home</a>

lighthouse-cli/test/smokehouse/test-definitions/a11y.js

@@ -476,7 +476,7 @@ const expectations = {
               node: {
                 'type': 'node',
                 'selector': 'body > section > input#form-field-multiple-labels',
-                'path': '2,HTML,1,BODY,43,SECTION,2,INPUT',
+                'path': '2,HTML,1,BODY,45,SECTION,2,INPUT',
                 'snippet': '<input type="checkbox" id="form-field-multiple-labels">',
                 'explanation': 'Fix all of the following:\n  Multiple label elements is not widely supported in assistive technologies. Ensure the first label contains all necessary information.',
                 'nodeLabel': 'body > section > input#form-field-multiple-labels',
@@ -487,7 +487,7 @@ const expectations = {
                   {
                     relatedNode: {
                       'type': 'node',
-                      'path': '2,HTML,1,BODY,43,SECTION,0,LABEL',
+                      'path': '2,HTML,1,BODY,45,SECTION,0,LABEL',
                       'selector': 'body > section > label#label1',
                       'snippet': '<label for="form-field-multiple-labels" id="label1">',
                       'nodeLabel': 'label1',
@@ -496,7 +496,7 @@ const expectations = {
                   {
                     relatedNode: {
                       'type': 'node',
-                      'path': '2,HTML,1,BODY,43,SECTION,1,LABEL',
+                      'path': '2,HTML,1,BODY,45,SECTION,1,LABEL',
                       'selector': 'body > section > label',
                       'snippet': '<label for="form-field-multiple-labels">',
                       'nodeLabel': 'label2',
@@ -532,7 +532,7 @@ const expectations = {
               node: {
                 'type': 'node',
                 'selector': 'body > section > h3',
-                'path': '2,HTML,1,BODY,47,SECTION,1,H3',
+                'path': '2,HTML,1,BODY,51,SECTION,1,H3',
                 'snippet': '<h3>',
                 'explanation': 'Fix any of the following:\n  Heading order invalid',
                 'nodeLabel': 'sub-sub-header',
@@ -751,6 +751,27 @@ const expectations = {
           ],
         },
       },
+      'frame-focusable-content': {
+        score: null,
+        scoreDisplayMode: 'notApplicable',
+      },
+      'empty-table-header': {
+        score: null,
+        details: {
+          items: [
+            {
+              node: {
+                'type': 'node',
+                'selector': 'table > tbody > tr > th',
+                'path': '2,HTML,1,BODY,43,SECTION,0,TABLE,0,TBODY,0,TR,0,TH',
+                'snippet': '<th>',
+                'explanation': 'Fix any of the following:\n  Element does not have text that is visible to screen readers',
+                'nodeLabel': 'table > tbody > tr > th',
+              },
+            },
+          ],
+        },
+      },
     },
   },
 };

lighthouse-cli/test/smokehouse/test-definitions/dobetterweb.js

@@ -391,11 +391,11 @@ const expectations = {
       },
       'dom-size': {
         score: 1,
-        numericValue: 153,
+        numericValue: 158,
         details: {
           items: [
-            {statistic: 'Total DOM Elements', value: 153},
-            {statistic: 'Maximum DOM Depth', value: 4},
+            {statistic: 'Total DOM Elements', value: 158},
+            {statistic: 'Maximum DOM Depth', value: 5},
             {
               statistic: 'Maximum Child Elements',
               value: 100,

lighthouse-core/audits/accessibility/empty-table-header.js

@@ -0,0 +1,44 @@
+/**
+ * @license Copyright 2021 The Lighthouse Authors. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
+ */
+'use strict';
+
+/**
+ * @fileoverview Ensures table headers have discernible text.
+ * See base class in axe-audit.js for audit() implementation.
+ */
+
+const AxeAudit = require('./axe-audit.js');
+const i18n = require('../../lib/i18n/i18n.js');
+
+const UIStrings = {
+  /** Title of an accesibility audit that checks if there are any table headers without visible text. This title is descriptive of the successful state and is shown to users when no user action is required. */
+  title: '`table` headers have visible text',
+  /** Title of an accesibility audit that checks if there are any table headers without visible text. This title is descriptive of the failing state and is shown to users when there is a failure that needs to be addressed. */
+  failureTitle: '`table` headers do not have visible text',
+  /** Description of a Lighthouse audit that tells the user *why* they should try to pass. This is displayed after a user expands the section to see more. No character length limits. 'Learn More' becomes link text to additional documentation. */
+  description: '`table` headers should have visible text so assistive technologies like screen readers may describe table contents appropriately. [Learn more](https://dequeuniversity.com/rules/axe/4.2/empty-table-header).',
+};
+
+const str_ = i18n.createMessageInstanceIdFn(__filename, UIStrings);
+
+class EmptyTableHeader extends AxeAudit {
+  /**
+   * @return {LH.Audit.Meta}
+   */
+  static get meta() {
+    return {
+      id: 'empty-table-header',
+      title: str_(UIStrings.title),
+      failureTitle: str_(UIStrings.failureTitle),
+      description: str_(UIStrings.description),
+      scoreDisplayMode: AxeAudit.SCORING_MODES.INFORMATIVE,
+      requiredArtifacts: ['Accessibility'],
+    };
+  }
+}
+
+module.exports = EmptyTableHeader;
+module.exports.UIStrings = UIStrings;

lighthouse-core/audits/accessibility/frame-focusable-content.js

@@ -0,0 +1,43 @@
+/**
+ * @license Copyright 2021 The Lighthouse Authors. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
+ */
+'use strict';
+
+/**
+ * @fileoverview No `<iframe tabindex=-1>` has focusable content.
+ * See base class in axe-audit.js for audit() implementation.
+ */
+
+const AxeAudit = require('./axe-audit.js');
+const i18n = require('../../lib/i18n/i18n.js');
+
+const UIStrings = {
+  /** Title of an accesibility audit that checks if there are any iframes with focusable content that mistakenly set tabindex = -1. This title is descriptive of the successful state and is shown to users when no user action is required. */
+  title: '`<iframe>` elements with focusable content do not have a negative `tabindex`',
+  /** Title of an accesibility audit that checks if there are any iframes with focusable content that mistakently set tabindex = -1. This title is descriptive of the failing state and is shown to users when there is a failure that needs to be addressed. */
+  failureTitle: '`<iframe>` elements with focusable content have a negative `tabindex`',
+  /** Description of a Lighthouse audit that tells the user *why* they should try to pass. This is displayed after a user expands the section to see more. No character length limits. 'Learn More' becomes link text to additional documentation. */
+  description: 'Focusable elements within an `<iframe>` element with a negative `tabindex` cannot be reached via keyboard navigation. [Learn more](https://dequeuniversity.com/rules/axe/4.2/frame-focusable-content).',
+};
+
+const str_ = i18n.createMessageInstanceIdFn(__filename, UIStrings);
+
+class FrameFocusableContent extends AxeAudit {
+  /**
+   * @return {LH.Audit.Meta}
+   */
+  static get meta() {
+    return {
+      id: 'frame-focusable-content',
+      title: str_(UIStrings.title),
+      failureTitle: str_(UIStrings.failureTitle),
+      description: str_(UIStrings.description),
+      requiredArtifacts: ['Accessibility'],
+    };
+  }
+}
+
+module.exports = FrameFocusableContent;
+module.exports.UIStrings = UIStrings;

lighthouse-core/config/default-config.js

@@ -256,7 +256,9 @@ const defaultConfig = {
     'accessibility/document-title',
     'accessibility/duplicate-id-active',
     'accessibility/duplicate-id-aria',
+    'accessibility/empty-table-header',
     'accessibility/form-field-multiple-labels',
+    'accessibility/frame-focusable-content',
     'accessibility/frame-title',
     'accessibility/heading-order',
     'accessibility/html-has-lang',
@@ -516,7 +518,9 @@ const defaultConfig = {
         {id: 'document-title', weight: 3, group: 'a11y-names-labels'},
         {id: 'duplicate-id-active', weight: 3, group: 'a11y-navigation'},
         {id: 'duplicate-id-aria', weight: 10, group: 'a11y-aria'},
+        {id: 'empty-table-header', weight: 2, group: 'a11y-tables-lists'},
         {id: 'form-field-multiple-labels', weight: 2, group: 'a11y-names-labels'},
+        {id: 'frame-focusable-content', weight: 3, group: 'a11y-navigation'},
         {id: 'frame-title', weight: 3, group: 'a11y-names-labels'},
         {id: 'heading-order', weight: 2, group: 'a11y-navigation'},
         {id: 'html-has-lang', weight: 3, group: 'a11y-language'},

lighthouse-core/gather/gatherers/accessibility.js

@@ -57,9 +57,9 @@ async function runA11yChecks() {
       'svg-img-alt': {enabled: false},
       'audio-caption': {enabled: false},
       'aria-treeitem-name': {enabled: true},
+      'empty-table-header': {enabled: true},
       // https://github.com/dequelabs/axe-core/issues/2958
       'nested-interactive': {enabled: false},
-      'frame-focusable-content': {enabled: false},
     },
   });
 

lighthouse-core/test/fraggle-rock/scenarios/api-test-pptr.js

@@ -47,7 +47,7 @@ describe('Fraggle Rock API', () => {
 
       const {auditResults, erroredAudits, failedAudits} = getAuditsBreakdown(lhr);
       // TODO(FR-COMPAT): This assertion can be removed when full compatibility is reached.
-      expect(auditResults.length).toMatchInlineSnapshot(`73`);
+      expect(auditResults.length).toMatchInlineSnapshot(`75`);
 
       expect(erroredAudits).toHaveLength(0);
       expect(failedAudits.map(audit => audit.id)).toContain('label');
@@ -147,7 +147,7 @@ describe('Fraggle Rock API', () => {
       const {lhr} = result;
       const {auditResults, failedAudits, erroredAudits} = getAuditsBreakdown(lhr);
       // TODO(FR-COMPAT): This assertion can be removed when full compatibility is reached.
-      expect(auditResults.length).toMatchInlineSnapshot(`152`);
+      expect(auditResults.length).toMatchInlineSnapshot(`154`);
       expect(erroredAudits).toHaveLength(0);
 
       const failedAuditIds = failedAudits.map(audit => audit.id);