[enzyme-adapter-react-16] [fix] properly render memoized SFCs

Fixes #2038

Author: ljharb

packages/enzyme-adapter-react-16/src/ReactSixteenAdapter.js

@@ -177,16 +177,21 @@ function toTree(vnode) {
  instance: node.stateNode,
  rendered: childrenToTree(node.child.child),
  };
- case FiberTags.MemoSFC:
+ case FiberTags.MemoSFC: {
+ let renderedNodes = flatten(nodeAndSiblingsArray(node.child).map(toTree));
+ if (renderedNodes.length === 0) {
+ renderedNodes = [node.memoizedProps.children];
+ }
  return {
  nodeType: 'function',
  type: node.elementType.type,
  props: { ...node.memoizedProps },
  key: ensureKeyOrUndefined(node.key),
  ref: node.ref,
  instance: null,
- rendered: childrenToTree(node.child.child),
+ rendered: renderedNodes,
  };
+ }
  case FiberTags.HostComponent: {
  let renderedNodes = flatten(nodeAndSiblingsArray(node.child).map(toTree));
  if (renderedNodes.length === 0) {

packages/enzyme-test-suite/test/ReactWrapper-spec.jsx

@@ -601,18 +601,20 @@ describeWithDOM('mount', () => {
 
  const wrapper = mount(<Foo foo="qux" />);
  expect(wrapper.debug()).to.equal(`<InnerFoo foo="qux">
- <InnerComp>
- <div>
- <span>
- Hello
- </span>
+ <div>
+ <InnerComp>
+ <div>
+ <span>
+ Hello
+ </span>
+ </div>
+ </InnerComp>
+ <div className="bar">
+ bar
+ </div>
+ <div className="qoo">
+ qux
  </div>
- </InnerComp>
- <div className="bar">
- bar
- </div>
- <div className="qoo">
- qux
  </div>
 </InnerFoo>`);
  expect(wrapper.find('InnerComp')).to.have.lengthOf(1);

packages/enzyme-test-suite/test/shared/methods/find.jsx

@@ -857,8 +857,7 @@ export default function describeFind({
  });
 
  describeIf(is('>= 16.6'), 'React.memo', () => {
- // FIXME: fix bug for mount
- itIf(!isMount, 'works with an SFC', () => {
+ it('works with an SFC', () => {
  const InnerComp = () => <div><span>Hello</span></div>;
  const InnerFoo = ({ foo }) => (
  <div>