Add Cross-Origin Iframe Fixture

fixtures/dom/src/components/fixtures/selection-events/CrossOriginFrameTestCase.js

@@ -0,0 +1,36 @@
+import TestCase from '../../TestCase';
+const React = window.React;
+
+export default class CrossOriginFrameTestCase extends React.Component {
+  state = {count: 0};
+
+  componentDidMount() {
+    this.interval = setInterval(() => {
+      this.setState(state => ({count: state.count + 1}));
+    }, 2000);
+  }
+
+  componentWillUnmount() {
+    clearInterval(this.interval);
+  }
+
+  render() {
+    return (
+      <TestCase
+        title="Selection within cross-origin iframes work"
+        description=""
+        affectedBrowsers="Safari"
+        relatedIssues="14002">
+        <TestCase.Steps>
+          <li>Select text in the iframe below</li>
+          <li>Open DevTools</li>
+          <li>Wait for the counter to tick: {this.state.count}</li>
+        </TestCase.Steps>
+        <TestCase.ExpectedResult>
+          No error is logged to the console.
+        </TestCase.ExpectedResult>
+        <iframe src="https://example.com/" />
+      </TestCase>
+    );
+  }
+}

fixtures/dom/src/components/fixtures/selection-events/index.js

@@ -1,6 +1,7 @@
 import FixtureSet from '../../FixtureSet';
 import ReorderedInputsTestCase from './ReorderedInputsTestCase';
 import OnSelectEventTestCase from './OnSelectEventTestCase';
+import CrossOriginFrameTestCase from './CrossOriginFrameTestCase';
 const React = window.React;
 
 export default function SelectionEvents() {
@@ -14,6 +15,7 @@ export default function SelectionEvents() {
       ">
       <ReorderedInputsTestCase />
       <OnSelectEventTestCase />
+      <CrossOriginFrameTestCase />
     </FixtureSet>
   );
 }