It seems problematic to allow arbitary non-lowercase attribute on HTML nodes. Because the server has no ability to keep them case sensitive (HTML isn't). So they will end up different on the client.

We should probably warn if the attribute is not a known one *and* is not lowercase.
render() {
          
          return <div id="classWrongChild">{this.context.text}</div>;
        }
      }
      ClassChildWithWrongContext.contextTypes = {foo: PropTypes.string};
      const e = await render(
        <PurpleContext><ClassChildWithWrongContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('');
    });
    itRenders('stateless child with wrong context', async render => {
      function StatelessChildWithWrongContext(props, context) {
        
        return <div id="statelessWrongChild">{context.text}</div>;
      }
      StatelessChildWithWrongContext.contextTypes = {
        foo: PropTypes.string,
      };
      const e = await render(
        <PurpleContext><StatelessChildWithWrongContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('');
    });
    itRenders('with context passed through to a grandchild', async render => {
      function Grandchild(props, context) {