trying to make a custom widget

I am trying to make a custom widget and I am having trouble. I am following tutorials on this. but the tutorial says that I should have a widget but when I check the admin area, i get an error saying that the widget can’t be found in wp-includes/widgets.php on line 324

here is my code

`
class bigBusiness_widgets extends WP_Widget {
	function bigBusiness_testimonial(){
		parent::WP_Widget(false, 'Testimonials');
	}
	function form($instance) {
		//outputs the options form on admin

	}
	function update($new_instance, $old_instance){
		//processes widget options to be saved
		return $new_instance;
	}
	function widget($args, $instance) {
		//outputs the content of the widget
	}
}
register_widget('bigBusiness_testimonial');
`