Add failing tests to highlight issue #11789

Author: magicmark

packages/react-dom/src/__tests__/ReactDOMTextComponent-test.js

@@ -197,6 +197,18 @@ describe('ReactDOMTextComponent', () => {
     expect(el.textContent).toBe('');
   });
 
+  it('can reconcile text from pre-rendered markup using dangerouslySetInnerHTML and an object with toString', () => {
+    const HelloObject = { toString: () => "Hello" };
+    const el = document.createElement('div');
+    let reactEl = (
+      <p dangerouslySetInnerHTML={{__html: HelloObject }} />
+    );
+    el.innerHTML = ReactDOMServer.renderToString(reactEl);
+
+    ReactDOM.hydrate(reactEl, el);
+    expect(el.textContent).toBe('Hello');
+  });
+
   xit('can reconcile text arbitrarily split into multiple nodes', () => {
     const el = document.createElement('div');
     let inst = ReactDOM.render(

packages/react-dom/src/client/__tests__/dangerouslySetInnerHTML-test.js

@@ -91,4 +91,14 @@ describe('dangerouslySetInnerHTML', () => {
       expect(circle.tagName).toBe('circle');
     });
   });
+
+  it('when rendering an object with a toString method', () => {
+    const container = document.createElement('div');
+    const HelloObject = {toString: () => 'Hello'};
+    const node = ReactDOM.render(
+      <div dangerouslySetInnerHTML={{__html: HelloObject}} />,
+      container,
+    );
+    expect(node.textContent).toBe('Hello');
+  });
 });