Tried to write a very basic plugin, help please plugin gurus !

I tried to write a very basic plugin, taking information from the net. For the moment I am yet to add any proper code, and first I was checking if things were working. I found its not working, both of the below functions failed to load.

Both eo.php (the file with the following codes) and eos.css are in the same folder : wp-content/plugins/eo/

if( !function_exists('eo')){
    	function eo($text) {
    		$text = str_replace('Test', 'Best', $text);
    		return $text;
    	}
    	add_filter('the_content', 'eo');
    }

    if( !function_exists('eos')){
    	function eos( ){
    		wp_register_style( 'eo', plugins_url('eo/eo.css', __DIR__) );
    		wp_enqueue_style( 'eo' );
    	}
    	add_action( 'wp_enqueue_scripts', 'eos' );
    }

And then question, can I load a js file along with like this ?

if( !function_exists('eos')){
        	function eos( ){
        		wp_register_style( 'eo', plugins_url('eo/eo.css', __DIR__) );
    			wp_register_script( 'eojs', plugins_url('eo/eo.js', __DIR__) );
        		wp_enqueue_script( 'eo' );
    			wp_enqueue_script( 'eojs' );
        	}
        	add_action( 'wp_enqueue_scripts', 'eos' );
    }

Any help will be welcomed
Thanks a lot ??