toHaveAttribute( received, prop, source ) {
      const pass = Boolean( received );
      return expectReturn( pass,
        `[${ source }] expected ${ JSON.stringify( prop ) } to be present`,
        `[${ source }] expected ${ JSON.stringify( prop ) } to be absent` );
    }
Assert value is truthy
@param {Boolean} received
@param {String} prop - property/attribute
@param {String} source
@returns {Object}