Fix traversal order, remove focus mocks

Author: jackpope

packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js

@@ -1659,16 +1659,17 @@ function recursivelyGetFragmentInstanceChildren(
     return;
   }
 
+  if (child.tag === HostComponent) {
+    childElements.add(child.stateNode);
+  }
+
   if (child.sibling !== null) {
     recursivelyGetFragmentInstanceChildren(child.sibling, childElements);
   }
 
-  if (child.tag === HostComponent) {
-    childElements.add(child.stateNode);
-    return;
+  if (child.tag !== HostComponent) {
+    recursivelyGetFragmentInstanceChildren(child.child, childElements);
   }
-
-  recursivelyGetFragmentInstanceChildren(child.child, childElements);
 }
 
 function normalizeListenerOptions(

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

@@ -96,13 +96,13 @@ describe('FragmentRefs', () => {
       const parentRef = React.createRef();
       const fragmentRef = React.createRef();
       const root = ReactDOMClient.createRoot(container);
-      let focusedElement = null;
 
       function Test() {
         return (
           <div ref={parentRef}>
             <Fragment ref={fragmentRef}>
               <div id="child-a" />
+              <style>{`#child-c {}`}</style>
               <a id="child-b" href="/">
                 B
               </a>
@@ -118,24 +118,10 @@ describe('FragmentRefs', () => {
         root.render(<Test />);
       });
 
-      // The test environment doesn't implement focus.
-      // Mock it here, along with a naive focusable query so we can assert
-      // that the first _focusable_ element is found.
-      const focusableChildren = parentRef.current.querySelectorAll(
-        'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])',
-      );
-      const focusMock = jest.spyOn(HTMLElement.prototype, 'focus');
-      focusMock.mockImplementation(function () {
-        if (Array.from(focusableChildren).includes(this)) {
-          focusedElement = this.id;
-        } else {
-          return false;
-        }
-      });
       await act(() => {
         fragmentRef.current.focus();
       });
-      expect(focusedElement).toEqual('child-b');
+      expect(document.activeElement.id).toEqual('child-b');
     });
 
     // @gate enableFragmentRefs