AMP_Image_Dimension_Extractor::get_default_user_agent PHP Method

    public static function get_default_user_agent()
    {
        return 'amp-wp, v' . AMP__VERSION . ', ' . get_site_url();
    }

 function test__amp_wp_user_agent()
 {
     $expected = 'amp-wp, v' . AMP__VERSION . ', ';
     $user_agent = AMP_Image_Dimension_Extractor::get_default_user_agent('');
     $user_agent = substr($user_agent, 0, strlen($expected));
     $this->assertEquals($expected, $user_agent);
 }