gistfile1.js

var good = 0,
    bad = 0,
    reqtime;
function post() {
    reqtime = new Date().getTime();
    $.when( $.post( 'https://graph.facebook.com/YOUR_APP_ID/accounts/test-users', {
        locale: 'en_US',
        access_token: 'YOUR_ACCESS_TOKEN',
        installed: true,
        permissions: 'read_stream,email,user_likes,user_interests',
        name: 'Existing User'
    }) ).then(function( a,b,c ) {
        console.log('SUCCESS', ( new Date().getTime() - reqtime) + ' ms' );
        good++;
    }).fail(function( a,b,c ) {
        console.log(
            'FAIL',a,b,c, ( new Date().getTime() - reqtime) + ' ms. ' + good + '/' + bad + ' successes / fails (' +
            ((bad / (good + bad)) * 100) + '%)'
        );
        bad++;
    }).always(function( a,b,c ) {
        post();
    });
}
post();