added 2 more tests for hasClass on composite components

- passing test for composite component that renders composite component which itself renders a dom element
- failing test for composite component that renders null

test/ReactWrapper-spec.jsx

@@ -2105,6 +2105,42 @@ describeWithDOM('mount', () => {
         expect(wrapper.hasClass('doesnt-exist')).to.equal(false);
       });
     });
+
+    context('When using nested composite components', () => {
+      it('should return whether or not node has a certain class', () => {
+        class Foo extends React.Component {
+          render() {
+            return (<div className="foo bar baz some-long-string FoOo" />);
+          }
+        }
+        class Bar extends React.Component {
+          render() {
+            return <Foo />;
+          }
+        }
+        const wrapper = mount(<Bar />);
+
+        expect(wrapper.hasClass('foo')).to.equal(true);
+        expect(wrapper.hasClass('bar')).to.equal(true);
+        expect(wrapper.hasClass('baz')).to.equal(true);
+        expect(wrapper.hasClass('some-long-string')).to.equal(true);
+        expect(wrapper.hasClass('FoOo')).to.equal(true);
+        expect(wrapper.hasClass('doesnt-exist')).to.equal(false);
+      });
+    });
+
+    context('When using a Composite component that renders null', () => {
+      it('should return whether or not node has a certain class', () => {
+        class Foo extends React.Component {
+          render() {
+            return null;
+          }
+        }
+        const wrapper = mount(<Foo />);
+
+        expect(wrapper.hasClass('foo')).to.equal(false);
+      });
+    });
   });
 
   describe('.forEach(fn)', () => {