PHP(wordpress): testing wp_mail function

script in root of WP

<?php
        
        // Set $to as the email you want to send the test to.

$to = "you@yourdomain.com" ;

       // No need to make changes below this line.
       // Email subject and body text.

$subject = ' wp_mail function test ' ;
$message = ' This is a test of the wp_mail function: wp_mail is working ' ;
$headers = '' ;

      // Load WP components, no themes.

define ('WP_USE_THEMES', false);

require('wp-load.php');

     // send test message using wp_mail function.

$sent_message = wp_mail( $to, $subject, $message, $headers);

     //display message based on the result.

if ( $sent_message ) {

    // The message was sent.
echo 'The test message was sent. Check your email inbox.' ;

} else {

    // The message was not sent.
echo 'The message was not sent!' ;
}

http://www.butlerblog.com/2011/07/08/changing-the-wp_mail-from-address-in-wordpress-without-a-plugin