I would assume that test data would be localized via wp_localize_script
so the test data is fully available on page load. Here's what I'd imagine the enqueues to be:
wp_localize_script( 'go-ab-testing', 'go_ab_testing', array( 'tests' => $variations ) );
wp_enqueue_script( 'go-ab-testing' );
if ( 'undefined' == typeof go_ab_testing ) {
var go_ab_testing = {};