how to use wc_create_order with subscription product

Here’s my code for creating a subscription — it took a lot of trial and error to figure it all out. Best of luck!

function create_test_sub() {

    $email="[email protected]";

    $start_date="2015-01-01 00:00:00";

    $address = array(
        'first_name' => 'Jeremy',
        'last_name'  => 'Test',
        'company'    => '',
        'email'      => $email,
        'phone'      => '777-777-777-777',
        'address_1'  => '31 Main Street',
        'address_2'  => '', 
        'city'       => 'Auckland',
        'state'      => 'AKL',
        'postcode'   => '12345',
        'country'    => 'AU'
    );

    $default_password = wp_generate_password();

    if (!$user = get_user_by('login', $email)) $user = wp_create_user( $email, $default_password, $email );

    // I've used one product with multiple variations

    $parent_product = wc_get_product(22998);

    $args = array(
        'attribute_billing-period' => 'Yearly',
        'attribute_subscription-type' => 'Both'
    );

    $product_variation = $parent_product->get_matching_variation($args);

    $product = wc_get_product($product_variation);  

    // Each variation also has its own shipping class

    $shipping_class = get_term_by('slug', $product->get_shipping_class(), 'product_shipping_class');

    WC()->shipping->load_shipping_methods();
    $shipping_methods = WC()->shipping->get_shipping_methods();

    // I have some logic for selecting which shipping method to use; your use case will likely be different, so figure out the method you need and store it in $selected_shipping_method

    $selected_shipping_method = $shipping_methods['free_shipping'];

    $class_cost = $selected_shipping_method->get_option('class_cost_' . $shipping_class->term_id);

    $quantity = 1;

    // As far as I can see, you need to create the order first, then the sub

    $order = wc_create_order(array('customer_id' => $user->id));

    $order->add_product( $product, $quantity, $args);
    $order->set_address( $address, 'billing' );
    $order->set_address( $address, 'shipping' );

    $order->add_shipping((object)array (
        'id' => $selected_shipping_method->id,
        'label'    => $selected_shipping_method->title,
        'cost'     => (float)$class_cost,
        'taxes'    => array(),
        'calc_tax'  => 'per_order'
    ));

    $order->calculate_totals();

    $order->update_status("completed", 'Imported order', TRUE);

    // Order created, now create sub attached to it -- optional if you're not creating a subscription, obvs

    // Each variation has a different subscription period

    $period = WC_Subscriptions_Product::get_period( $product );
    $interval = WC_Subscriptions_Product::get_interval( $product );

    $sub = wcs_create_subscription(array('order_id' => $order->id, 'billing_period' => $period, 'billing_interval' => $interval, 'start_date' => $start_date));

    $sub->add_product( $product, $quantity, $args);
    $sub->set_address( $address, 'billing' );
    $sub->set_address( $address, 'shipping' );

    $sub->add_shipping((object)array (
        'id' => $selected_shipping_method->id,
        'label'    => $selected_shipping_method->title,
        'cost'     => (float)$class_cost,
        'taxes'    => array(),
        'calc_tax'  => 'per_order'
    ));

    $sub->calculate_totals();

    WC_Subscriptions_Manager::activate_subscriptions_for_order($order);

    print "<a href="https://wordpress.stackexchange.com/wp-admin/post.php?post=" . $sub->id . "&action=edit">Sub created! Click here to edit</a>";
}