When setting boolean attributes on Web Components
`<x-search somebool name={this.props.name} />`
they get rendered as attribute/value pairs instead
`<x-search somebool="true" name={this.props.name}>`

This causes problems with some AMP components, for eg. `<amp-iframe />` which has a `resizable` attribute that gets rendered as `resizable="true"`. This results in non valid AMP content and developers crying with blood tears on their keyboards :)
> The attribute 'resizable' in tag 'amp-iframe' is set to the invalid value 'true'. (see https://www.ampproject.org/docs/reference/components/amp-iframe)

Is there any reason for the current behaviour? Will changing this break something else?
});
      itRenders('no download prop with function value', async render => {
        const e = await render(<div download={function() {}} />, 1);
        expect(e.hasAttribute('download')).toBe(false);
      });
      itRenders('no download prop with symbol value', async render => {
        const e = await render(<div download={Symbol('foo')} />, 1);
        expect(e.hasAttribute('download')).toBe(false);
      });
    });
    describe('className property', function() {
      itRenders('className prop with string value', async render => {
        const e = await render(<div className="myClassName" />);
        expect(e.getAttribute('class')).toBe('myClassName');
      });
      itRenders('className prop with empty string value', async render => {
        const e = await render(<div className="" />);
        expect(e.getAttribute('class')).toBe('');
      });
      itRenders('no className prop with true value', async render => {
        const e = await render(<div className={true} />, 1);
        expect(e.hasAttribute('class')).toBe(false);
      });
      itRenders('no className prop with false value', async render => {
        const e = await render(<div className={false} />, 1);
        expect(e.hasAttribute('class')).toBe(false);
      });
      itRenders('no className prop with null value', async render => {
        const e = await render(<div className={null} />);
        expect(e.hasAttribute('className')).toBe(false);