add tests confirming you can hydrate without a head

gnoff · gnoff · commit 36e6c1d47e06 · 2022-10-20T23:03:27.000-07:00
diff --git a/packages/react-dom/src/__tests__/ReactDOMSingletonComponents-test.js b/packages/react-dom/src/__tests__/ReactDOMSingletonComponents-test.js
@@ -975,4 +975,37 @@ describe('ReactDOM HostSingleton', () => {
       </html>,
     );
   });
+
+  // @gate enableHostSingletons
+  it('allows for hydrating without a head', async () => {
+    await actIntoEmptyDocument(() => {
+      const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
+        <html>
+          <body>foo</body>
+        </html>,
+      );
+      pipe(writable);
+    });
+
+    expect(getVisibleChildren(document)).toEqual(
+      <html>
+        <head />
+        <body>foo</body>
+      </html>,
+    );
+
+    ReactDOMClient.hydrateRoot(
+      document,
+      <html>
+        <body>foo</body>
+      </html>,
+    );
+    expect(Scheduler).toFlushWithoutYielding();
+    expect(getVisibleChildren(document)).toEqual(
+      <html>
+        <head />
+        <body>foo</body>
+      </html>,
+    );
+  });
 });
