Add shallow tests

Author: jquense

packages/enzyme-test-suite/package.json

@@ -49,4 +49,4 @@
     "eslint-plugin-jsx-a11y": "^6.0.3",
     "eslint-plugin-react": "^7.6.1"
   }
-}
+}

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

@@ -6,9 +6,9 @@ import { shallow, render, ShallowWrapper, mount } from 'enzyme';
 import { ITERATOR_SYMBOL, withSetStateAllowed, sym } from 'enzyme/build/Utils';
 
 import './_helpers/setupAdapters';
-import { createClass } from './_helpers/react-compat';
+import { createClass, createContext } from './_helpers/react-compat';
 import { describeIf, itIf, itWithData, generateEmptyRenderData } from './_helpers';
-import { REACT013, REACT014, REACT15, REACT150_4, REACT16, is } from './_helpers/version';
+import { REACT013, REACT014, REACT15, REACT150_4, REACT16, REACT163, is } from './_helpers/version';
 
 // The shallow renderer in react 16 does not yet support batched updates. When it does,
 // we should be able to go un-skip all of the tests that are skipped with this flag.
@@ -96,6 +96,22 @@ describe('shallow', () => {
       expect(wrapper.context('name')).to.equal(context.name);
     });
 
+    itIf(REACT163, 'should find elements through Context elements', () => {
+      const { Provider, Consumer } = createContext('');
+
+      class Foo extends React.Component {
+        render() {
+          return (
+            <Consumer>{value => <span>{value}</span>}</Consumer>
+          );
+        }
+      }
+
+      const wrapper = mount(<Provider value="foo"><div><Foo /></div></Provider>);
+
+      expect(wrapper.find('span').text()).to.equal('foo');
+    });
+
     describeIf(!REACT013, 'stateless function components', () => {
       it('can pass in context', () => {
         const SimpleComponent = (props, context) => (