[Fix] shallow/mount: default iterator should be iterable

Author: ljharb

Diff for: packages/enzyme-test-suite/test/ReactWrapper-spec.jsx

@@ -4018,6 +4018,26 @@ describeWithDOM('mount', () => {
       expect(c1).to.deep.equal(c);
       expect(d1).to.deep.equal(d);
     });
+
+    it('returns an iterable iterator', () => {
+      class Foo extends React.Component {
+        render() {
+          return (
+            <div>
+              <a href="#1">Hello</a>
+              <a href="#2">Hello</a>
+              <a href="#3">Hello</a>
+              <a href="#4">Hello</a>
+            </div>
+          );
+        }
+      }
+      const wrapper = mount(<Foo />);
+
+      const iter = wrapper[ITERATOR_SYMBOL]();
+      expect(iter).to.have.property(ITERATOR_SYMBOL).and.be.a('function');
+      expect(iter[ITERATOR_SYMBOL]()).to.equal(iter);
+    });
   });
 
   describe('.instance()', () => {

Diff for: packages/enzyme-test-suite/test/ShallowWrapper-spec.jsx

@@ -4973,6 +4973,26 @@ describe('shallow', () => {
       expect(c1).to.deep.equal(c);
       expect(d1).to.deep.equal(d);
     });
+
+    it('returns an iterable iterator', () => {
+      class Foo extends React.Component {
+        render() {
+          return (
+            <div>
+              <a href="#1">Hello</a>
+              <a href="#2">Hello</a>
+              <a href="#3">Hello</a>
+              <a href="#4">Hello</a>
+            </div>
+          );
+        }
+      }
+      const wrapper = shallow(<Foo />);
+
+      const iter = wrapper[ITERATOR_SYMBOL]();
+      expect(iter).to.have.property(ITERATOR_SYMBOL).and.be.a('function');
+      expect(iter[ITERATOR_SYMBOL]()).to.equal(iter);
+    });
   });
 
   describe('.getNodes()', () => {

Diff for: packages/enzyme/src/ReactWrapper.js

@@ -1062,6 +1062,7 @@ if (ITERATOR_SYMBOL) {
       const iter = this[NODES][ITERATOR_SYMBOL]();
       const adapter = getAdapter(this[OPTIONS]);
       return {
+        [ITERATOR_SYMBOL]() { return this; },
         next() {
           const next = iter.next();
           if (next.done) {

Diff for: packages/enzyme/src/ShallowWrapper.js

@@ -1264,6 +1264,7 @@ if (ITERATOR_SYMBOL) {
       const iter = this.getNodesInternal()[ITERATOR_SYMBOL]();
       const adapter = getAdapter(this[OPTIONS]);
       return {
+        [ITERATOR_SYMBOL]() { return this; },
         next() {
           const next = iter.next();
           if (next.done) {