Why can't Laravel 4 see my testing config in the apps/config folder?

I have followed the tutorial here, but any database connection is still hitting my primary development database locally.

http://ift.tt/1c80nlx

Under app/config/testing I have defined database.php as per this tutorial and still it isn't connecting properly.

<?php
return array(
    'default' => 'sqlite',
    'connections' => array(
        'sqlite' => array(
            'driver'   => 'sqlite',
            'database' => ':memory:',
            'prefix'   => '',
        ),
    )
);

My bootstrap/start.php is as follows:

$env = $app->detectEnvironment(array(
    'local' => array('macbook'),
));

According to everything I have read, Laravel should be able to define its own testing environment.

TIA.