From 4c90c3668a6044838d6e57239c54ae439a6f3b88 Mon Sep 17 00:00:00 2001
From: Chris Morrell <inxilpro@users.noreply.github.com>
Date: Mon, 6 Jan 2025 12:36:58 -0500
Subject: [PATCH] Add some new resources and examples

---
 composer.json                                 |   3 +
 docs/articles.md                              |   6 +
 docs/navigation.json                          |  43 +++--
 docs/videos.md                                |  12 ++
 examples/Cart/README.md                       |   4 +
 examples/Cart/navigation.json                 |  55 ++++++
 .../Cart/src/Console/Commands/ShopCommand.php |  96 ++++++++++
 examples/Cart/src/Events/CheckedOut.php       |  34 ++++
 examples/Cart/src/Events/ItemAddedToCart.php  |  50 +++++
 .../Cart/src/Events/ItemRemovedFromCart.php   |  35 ++++
 examples/Cart/src/Events/ItemRestocked.php    |  18 ++
 examples/Cart/src/States/CartState.php        |  17 ++
 examples/Cart/src/States/ItemState.php        |  27 +++
 examples/Cart/tests/CartTest.php              | 179 ++++++++++++++++++
 14 files changed, 558 insertions(+), 21 deletions(-)
 create mode 100644 docs/articles.md
 create mode 100644 docs/videos.md
 create mode 100644 examples/Cart/README.md
 create mode 100644 examples/Cart/navigation.json
 create mode 100644 examples/Cart/src/Console/Commands/ShopCommand.php
 create mode 100644 examples/Cart/src/Events/CheckedOut.php
 create mode 100644 examples/Cart/src/Events/ItemAddedToCart.php
 create mode 100644 examples/Cart/src/Events/ItemRemovedFromCart.php
 create mode 100644 examples/Cart/src/Events/ItemRestocked.php
 create mode 100644 examples/Cart/src/States/CartState.php
 create mode 100644 examples/Cart/src/States/ItemState.php
 create mode 100644 examples/Cart/tests/CartTest.php

diff --git a/composer.json b/composer.json
index 6f1c14ca..45df19c3 100644
--- a/composer.json
+++ b/composer.json
@@ -49,6 +49,9 @@
     "autoload-dev": {
         "psr-4": {
             "Thunk\\Verbs\\Tests\\": "tests/",
+            "Thunk\\Verbs\\Examples\\Cart\\": "examples/Cart/src/",
+            "Thunk\\Verbs\\Examples\\Cart\\Tests\\": "examples/Cart/tests/",
+            "Thunk\\Verbs\\Examples\\Cart\\Database\\Factories\\": "examples/Cart/database/factories/",
             "Thunk\\Verbs\\Examples\\Counter\\": "examples/Counter/src/",
             "Thunk\\Verbs\\Examples\\Counter\\Tests\\": "examples/Counter/tests/",
             "Thunk\\Verbs\\Examples\\Counter\\Database\\Factories\\": "examples/Counter/database/factories/",
diff --git a/docs/articles.md b/docs/articles.md
new file mode 100644
index 00000000..314eb4f4
--- /dev/null
+++ b/docs/articles.md
@@ -0,0 +1,6 @@
+This is a collection of articles and blog posts that have been published about Verbs. If you have written something
+about Verbs, feel free to [submit a PR](https://github.com/hirethunk/verbs/blob/main/docs/articles.md) to add it
+to the list.
+
+- [Models in Verbs](https://cmorrell.com/models-in-verbs) (Chris Morrell - 2024)
+- [Verbs Validation Errors](https://cmorrell.com/verbs-errors) (Chris Morrell - 2024)
diff --git a/docs/navigation.json b/docs/navigation.json
index bf09b309..85d0ed4a 100644
--- a/docs/navigation.json
+++ b/docs/navigation.json
@@ -41,10 +41,32 @@
             }
         ]
     },
+    {
+        "title": "Resources",
+        "slug": "resources",
+        "items": [
+            {
+                "title": "Videos",
+                "slug": "videos",
+                "icon": "tv"
+            },
+            {
+                "title": "Articles",
+                "slug": "articles",
+                "icon": "newspaper"
+            }
+        ]
+    },
     {
         "title": "Examples",
         "slug": "examples",
         "items": [
+            {
+                "title": "Shopping Cart",
+                "slug": "cart",
+                "icon": "shopping-cart",
+                "url": "/examples/cart"
+            },
             {
                 "title": "Board Game",
                 "slug": "monopoly",
@@ -105,26 +127,5 @@
                 "icon": "circle-stack"
             }
         ]
-    },
-    {
-        "title": "Packages",
-        "slug": "verbs-packages",
-        "items": [
-            {
-                "title": "Verbs Commands",
-                "slug": "verbs-commands",
-                "icon": "window"
-            },
-            {
-                "title": "Verbs History",
-                "slug": "verbs-history",
-                "icon": "book-open"
-            },
-            {
-                "title": "Verbs Livewire",
-                "slug": "verbs-livewire",
-                "icon": "bolt"
-            }
-        ]
     }
 ]
diff --git a/docs/videos.md b/docs/videos.md
new file mode 100644
index 00000000..6a960790
--- /dev/null
+++ b/docs/videos.md
@@ -0,0 +1,12 @@
+> [!note]
+> These videos are relatively off-the-cuff and are using Verbs pre-releases. Some features
+> may change, or best practices may emerge prior to version 1.0 that will make these videos
+> obsolete. Once Verbs 1.0 is released, we plan on publishing a full, produced video series
+> on Verbs.
+
+-------
+
+Chris has posted a couple of introductory videos to YouTube. You can watch the playlist
+below, or [view it on YouTube](https://www.youtube.com/playlist?list=PLfp8k2-5wAK5Knn7HT43k1MJca08q_1nP).
+
+https://youtube.com/playlist?list=PLfp8k2-5wAK5Knn7HT43k1MJca08q_1nP&si=8wbEtU4Sz6Qp3A5_
diff --git a/examples/Cart/README.md b/examples/Cart/README.md
new file mode 100644
index 00000000..75155b28
--- /dev/null
+++ b/examples/Cart/README.md
@@ -0,0 +1,4 @@
+# Shopping Cart Example
+
+This example is the code written in Chris's [Using state in Verbs](https://www.youtube.com/watch?v=d6_ggotpb_8&t=594s)
+YouTube video. Tests and a few comments have been added.
diff --git a/examples/Cart/navigation.json b/examples/Cart/navigation.json
new file mode 100644
index 00000000..009b18d0
--- /dev/null
+++ b/examples/Cart/navigation.json
@@ -0,0 +1,55 @@
+[
+    {
+        "title": "Intro",
+        "slug": "intro",
+        "items": [
+            {
+                "title": "Shopping Cart Example",
+                "slug": "readme",
+                "path": "README.md"
+            }
+        ]
+    },
+    {
+        "title": "Events",
+        "slug": "events",
+        "items": [
+            {
+                "title": "ItemRestocked",
+                "slug": "restock",
+                "path": "src/Events/ItemRestocked.php"
+            },
+            {
+                "title": "ItemAddedToCart",
+                "slug": "add-to-cart",
+                "path": "src/Events/ItemAddedToCart.php"
+            },
+            {
+                "title": "ItemRemovedFromCart",
+                "slug": "remove-from-cart",
+                "path": "src/Events/ItemRemovedFromCart.php"
+            },
+            {
+                "title": "CheckedOut",
+                "slug": "checkout",
+                "path": "src/Events/CheckedOut.php"
+            }
+        ]
+    },
+    {
+        "title": "State",
+        "slug": "state",
+        "items": [
+            {
+                "title": "CartState",
+                "slug": "cart",
+                "path": "src/States/CartState.php"
+            },
+            {
+                "title": "ItemState",
+                "slug": "item",
+                "path": "src/States/ItemState.php"
+            }
+        ]
+    }
+]
diff --git a/examples/Cart/src/Console/Commands/ShopCommand.php b/examples/Cart/src/Console/Commands/ShopCommand.php
new file mode 100644
index 00000000..c42984d8
--- /dev/null
+++ b/examples/Cart/src/Console/Commands/ShopCommand.php
@@ -0,0 +1,96 @@
+<?php
+
+namespace Thunk\Verbs\Examples\Cart\Console\Commands;
+
+use Closure;
+use Exception;
+use Illuminate\Console\Command;
+use Thunk\Verbs\Examples\Cart\Events\CheckedOut;
+use Thunk\Verbs\Examples\Cart\Events\ItemAddedToCart;
+use Thunk\Verbs\Examples\Cart\Events\ItemRemovedFromCart;
+use Thunk\Verbs\Examples\Cart\Events\ItemRestocked;
+
+use function Laravel\Prompts\error;
+use function Laravel\Prompts\select;
+use function Laravel\Prompts\text;
+
+class ShopCommand extends Command
+{
+    protected $signature = 'shop';
+
+    protected int $cart_id;
+
+    protected array $stickers;
+
+    public function handle()
+    {
+        $this->setup();
+
+        do {
+            try {
+                $action = $this->action();
+                $this->getLaravel()->forgetScopedInstances(); // Emulate a new request
+                $action();
+            } catch (Exception $exception) {
+                error("Error: {$exception->getMessage()}");
+            }
+        } while (true);
+    }
+
+    protected function action(): Closure
+    {
+        $selection = select(
+            label: 'What would you like to do?',
+            options: [
+                'Add item to cart',
+                'Remove item from cart',
+                'Check out',
+                'Restock items',
+            ]
+        );
+
+        return match ($selection) {
+            'Add item to cart' => function () {
+                [$item, $quantity] = $this->selectSticker();
+                ItemAddedToCart::commit(cart: $this->cart_id, item: $item, quantity: $quantity);
+            },
+            'Remove item from cart' => function () {
+                [$item, $quantity] = $this->selectSticker();
+                ItemRemovedFromCart::commit(cart: $this->cart_id, item: $item, quantity: $quantity);
+            },
+            'Check out' => function () {
+                CheckedOut::commit(cart: $this->cart_id);
+            },
+            'Restock items' => function () {
+                [$sticker, $quantity] = $this->selectSticker(4);
+                ItemRestocked::commit(item: $sticker, quantity: (int) $quantity);
+            },
+        };
+    }
+
+    protected function selectSticker($default_quantity = 1): array
+    {
+        $sticker = select('Which sticker?', $this->stickers);
+        $quantity = (int) text('Quantity', default: $default_quantity, required: true, validate: ['quantity' => 'required|int|min:1']);
+
+        return [$sticker, $quantity];
+    }
+
+    protected function setup()
+    {
+        // Each time we load our app we'll create a new shopping cart by assigning
+        // it a unique ID.
+
+        $this->cart_id = snowflake_id();
+
+        // These are entirely arbitrary IDs. They're just hard-coded so that they're
+        // consistent across separate runs of the app.
+
+        $this->stickers = [
+            1000 => 'PHP×Philly',
+            1001 => 'Ignore Prev. Instructions',
+            1002 => 'Verbs',
+            1003 => 'Over Engineered',
+        ];
+    }
+}
diff --git a/examples/Cart/src/Events/CheckedOut.php b/examples/Cart/src/Events/CheckedOut.php
new file mode 100644
index 00000000..41b8f0ec
--- /dev/null
+++ b/examples/Cart/src/Events/CheckedOut.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Thunk\Verbs\Examples\Cart\Events;
+
+use Thunk\Verbs\Event;
+use Thunk\Verbs\Examples\Cart\States\CartState;
+use Thunk\Verbs\Examples\Cart\States\ItemState;
+
+class CheckedOut extends Event
+{
+    public CartState $cart;
+
+    public function validate()
+    {
+        $this->assert(! $this->cart->checked_out, 'Already checked out');
+
+        foreach ($this->cart->items as $item_id => $quantity) {
+            $item = ItemState::load($item_id);
+            $held = $item->activeHolds()[$this->cart->id]['quantity'] ?? 0;
+            $this->assert($held + $item->available() >= $quantity, 'Some items in your cart are out of stock');
+        }
+    }
+
+    public function apply()
+    {
+        foreach ($this->cart->items as $item_id => $quantity) {
+            $item = ItemState::load($item_id);
+            $item->quantity -= $quantity;
+            unset($item->holds[$this->cart->id]);
+        }
+
+        $this->cart->checked_out = true;
+    }
+}
diff --git a/examples/Cart/src/Events/ItemAddedToCart.php b/examples/Cart/src/Events/ItemAddedToCart.php
new file mode 100644
index 00000000..2a96b9dc
--- /dev/null
+++ b/examples/Cart/src/Events/ItemAddedToCart.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace Thunk\Verbs\Examples\Cart\Events;
+
+use Thunk\Verbs\Event;
+use Thunk\Verbs\Examples\Cart\States\CartState;
+use Thunk\Verbs\Examples\Cart\States\ItemState;
+
+class ItemAddedToCart extends Event
+{
+    public static int $item_limit = 2;
+
+    public static int $hold_seconds = 5;
+
+    public ItemState $item;
+
+    public CartState $cart;
+
+    public int $quantity;
+
+    public function validate()
+    {
+        $this->assert(! $this->cart->checked_out, 'Already checked out');
+
+        $this->assert(
+            $this->item->available() >= $this->quantity,
+            'Out of stock',
+        );
+
+        $this->assert(
+            $this->cart->count($this->item->id) + $this->quantity <= self::$item_limit,
+            'Reached limit'
+        );
+    }
+
+    public function apply()
+    {
+        // Add (additional?) quantity to cart
+        $this->cart->items[$this->item->id] = $this->cart->count($this->item->id) + $this->quantity;
+
+        // Initialize hold to 0 if it doesn't already exist
+        $this->item->holds[$this->cart->id] ??= [
+            'quantity' => 0,
+            'expires' => now()->unix() + self::$hold_seconds,
+        ];
+
+        // Add quantity to hold
+        $this->item->holds[$this->cart->id]['quantity'] += $this->quantity;
+    }
+}
diff --git a/examples/Cart/src/Events/ItemRemovedFromCart.php b/examples/Cart/src/Events/ItemRemovedFromCart.php
new file mode 100644
index 00000000..0f46a17a
--- /dev/null
+++ b/examples/Cart/src/Events/ItemRemovedFromCart.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Thunk\Verbs\Examples\Cart\Events;
+
+use Thunk\Verbs\Event;
+use Thunk\Verbs\Examples\Cart\States\CartState;
+use Thunk\Verbs\Examples\Cart\States\ItemState;
+
+class ItemRemovedFromCart extends Event
+{
+    public CartState $cart;
+
+    public ItemState $item;
+
+    public int $quantity;
+
+    public function validate()
+    {
+        $this->assert(! $this->cart->checked_out, 'Already checked out');
+
+        $this->assert(
+            $this->cart->count($this->item->id) >= $this->quantity,
+            "There aren't {$this->quantity} items in the cart to remove."
+        );
+    }
+
+    public function apply()
+    {
+        $this->cart->items[$this->item->id] -= $this->quantity;
+
+        if (isset($this->item->holds[$this->cart->id])) {
+            $this->item->holds[$this->cart->id]['quantity'] -= $this->quantity;
+        }
+    }
+}
diff --git a/examples/Cart/src/Events/ItemRestocked.php b/examples/Cart/src/Events/ItemRestocked.php
new file mode 100644
index 00000000..84ac49bc
--- /dev/null
+++ b/examples/Cart/src/Events/ItemRestocked.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Thunk\Verbs\Examples\Cart\Events;
+
+use Thunk\Verbs\Event;
+use Thunk\Verbs\Examples\Cart\States\ItemState;
+
+class ItemRestocked extends Event
+{
+    public ItemState $item;
+
+    public int $quantity;
+
+    public function apply()
+    {
+        $this->item->quantity += $this->quantity;
+    }
+}
diff --git a/examples/Cart/src/States/CartState.php b/examples/Cart/src/States/CartState.php
new file mode 100644
index 00000000..83f8cc2d
--- /dev/null
+++ b/examples/Cart/src/States/CartState.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace Thunk\Verbs\Examples\Cart\States;
+
+use Thunk\Verbs\State;
+
+class CartState extends State
+{
+    public array $items = [];
+
+    public bool $checked_out = false;
+
+    public function count(int $item_id): int
+    {
+        return $this->items[$item_id] ?? 0;
+    }
+}
diff --git a/examples/Cart/src/States/ItemState.php b/examples/Cart/src/States/ItemState.php
new file mode 100644
index 00000000..def379b0
--- /dev/null
+++ b/examples/Cart/src/States/ItemState.php
@@ -0,0 +1,27 @@
+<?php
+
+namespace Thunk\Verbs\Examples\Cart\States;
+
+use Thunk\Verbs\State;
+
+class ItemState extends State
+{
+    public int $quantity = 0;
+
+    public array $holds = [];
+
+    public function available(): int
+    {
+        return $this->quantity - $this->activeHoldCount();
+    }
+
+    public function activeHolds(): array
+    {
+        return $this->holds = array_filter($this->holds, fn ($hold) => $hold['expires'] > now()->unix());
+    }
+
+    protected function activeHoldCount(): mixed
+    {
+        return collect($this->activeHolds())->sum('quantity');
+    }
+}
diff --git a/examples/Cart/tests/CartTest.php b/examples/Cart/tests/CartTest.php
new file mode 100644
index 00000000..c36f3fa3
--- /dev/null
+++ b/examples/Cart/tests/CartTest.php
@@ -0,0 +1,179 @@
+<?php
+
+use Thunk\Verbs\Examples\Cart\Events\CheckedOut;
+use Thunk\Verbs\Examples\Cart\Events\ItemAddedToCart;
+use Thunk\Verbs\Examples\Cart\Events\ItemRemovedFromCart;
+use Thunk\Verbs\Examples\Cart\Events\ItemRestocked;
+use Thunk\Verbs\Examples\Cart\States\CartState;
+use Thunk\Verbs\Examples\Cart\States\ItemState;
+use Thunk\Verbs\Facades\Verbs;
+
+beforeEach(function () {
+    Verbs::commitImmediately();
+});
+
+it('can be restocked', function () {
+    $item = ItemState::load(snowflake_id());
+
+    $this->assertEquals(0, $item->quantity);
+
+    ItemRestocked::fire(item: $item, quantity: 4);
+
+    $this->assertEquals(4, $item->quantity);
+
+    ItemRestocked::fire(item: $item, quantity: 2);
+
+    $this->assertEquals(6, $item->quantity);
+});
+
+it('can have items added to it', function () {
+    $item = ItemState::load(snowflake_id());
+    $cart = CartState::load(snowflake_id());
+
+    $this->assertEquals(0, $item->available());
+    $this->assertEquals(0, $cart->count($item->id));
+
+    $this->assertThrows(fn () => ItemAddedToCart::fire(cart: $cart, item: $item, quantity: 4));
+
+    ItemRestocked::fire(item: $item, quantity: 4);
+
+    $this->assertEquals(4, $item->available());
+    $this->assertEquals(0, $cart->count($item->id));
+
+    ItemAddedToCart::fire(cart: $cart, item: $item, quantity: 2);
+
+    $this->assertEquals(2, $item->available());
+    $this->assertEquals(2, $cart->count($item->id));
+});
+
+it('enforces item limits', function () {
+    ItemAddedToCart::$item_limit = 2;
+
+    $item1 = ItemState::load(snowflake_id());
+    $item2 = ItemState::load(snowflake_id());
+    $cart = CartState::load(snowflake_id());
+
+    ItemRestocked::fire(item: $item1, quantity: 100);
+    ItemRestocked::fire(item: $item2, quantity: 100);
+
+    ItemAddedToCart::fire(cart: $cart, item: $item1, quantity: 2);
+    ItemAddedToCart::fire(cart: $cart, item: $item2, quantity: 2);
+
+    $this->assertThrows(fn () => ItemAddedToCart::fire(cart: $cart, item: $item1, quantity: 1));
+    $this->assertThrows(fn () => ItemAddedToCart::fire(cart: $cart, item: $item2, quantity: 1));
+});
+
+it('reserves items for a configured number of seconds', function () {
+    ItemAddedToCart::$hold_seconds = 10;
+    Date::setTestNow();
+
+    $item = ItemState::load(snowflake_id());
+    $cart1 = CartState::load(snowflake_id());
+    $cart2 = CartState::load(snowflake_id());
+
+    ItemRestocked::fire(item: $item, quantity: 2);
+
+    ItemAddedToCart::fire(cart: $cart1, item: $item, quantity: 2);
+
+    $this->assertThrows(fn () => ItemAddedToCart::fire(cart: $cart2, item: $item, quantity: 2));
+
+    Date::setTestNow(now()->addSeconds(11));
+
+    ItemAddedToCart::fire(cart: $cart2, item: $item, quantity: 2);
+
+    $this->assertEquals(2, $cart2->count($item->id));
+    $this->assertNotTrue(isset($item->activeHolds()[$cart1->id]));
+    $this->assertEquals(2, $item->activeHolds()[$cart2->id]['quantity']);
+});
+
+it('can have items removed from it', function () {
+    $item = ItemState::load(snowflake_id());
+    $cart = CartState::load(snowflake_id());
+
+    ItemRestocked::fire(item: $item, quantity: 2);
+
+    $this->assertThrows(fn () => ItemRemovedFromCart::fire(cart: $cart, item: $item, quantity: 1));
+
+    ItemAddedToCart::fire(cart: $cart, item: $item, quantity: 2);
+    ItemRemovedFromCart::fire(cart: $cart, item: $item, quantity: 1);
+
+    $this->assertEquals(1, $item->available());
+    $this->assertEquals(1, $cart->count($item->id));
+
+    ItemRemovedFromCart::fire(cart: $cart, item: $item, quantity: 1);
+
+    $this->assertThrows(fn () => ItemRemovedFromCart::fire(cart: $cart, item: $item, quantity: 1));
+});
+
+it('allows checking out', function () {
+    $cart = CartState::load(snowflake_id());
+    $item1 = ItemState::load(snowflake_id());
+    $item2 = ItemState::load(snowflake_id());
+
+    ItemRestocked::fire(item: $item1, quantity: 2);
+    ItemRestocked::fire(item: $item2, quantity: 2);
+
+    ItemAddedToCart::fire(cart: $cart, item: $item1, quantity: 2);
+    ItemAddedToCart::fire(cart: $cart, item: $item2, quantity: 2);
+
+    CheckedOut::fire(cart: $cart);
+
+    $this->assertEquals(0, $item1->available());
+    $this->assertEquals(0, collect($item1->activeHolds())->sum('quantity'));
+    $this->assertEquals(0, $item2->available());
+    $this->assertEquals(0, collect($item2->activeHolds())->sum('quantity'));
+});
+
+it('allows checking out after a hold expires if there is enough stock', function () {
+    ItemAddedToCart::$hold_seconds = 10;
+    Date::setTestNow();
+
+    $cart = CartState::load(snowflake_id());
+    $item1 = ItemState::load(snowflake_id());
+    $item2 = ItemState::load(snowflake_id());
+
+    ItemRestocked::fire(item: $item1, quantity: 2);
+    ItemRestocked::fire(item: $item2, quantity: 2);
+
+    ItemAddedToCart::fire(cart: $cart, item: $item1, quantity: 2);
+    ItemAddedToCart::fire(cart: $cart, item: $item2, quantity: 2);
+
+    Date::setTestNow(now()->addSeconds(11));
+
+    $this->assertNotTrue(isset($item1->activeHolds()[$cart->id]));
+    $this->assertNotTrue(isset($item2->activeHolds()[$cart->id]));
+
+    CheckedOut::fire(cart: $cart);
+
+    $this->assertEquals(0, $item1->available());
+    $this->assertEquals(0, collect($item1->activeHolds())->sum('quantity'));
+    $this->assertEquals(0, $item2->available());
+    $this->assertEquals(0, collect($item2->activeHolds())->sum('quantity'));
+});
+
+it('does not allow checking out if there is no stock', function () {
+    ItemAddedToCart::$hold_seconds = 10;
+    Date::setTestNow();
+
+    $cart1 = CartState::load(snowflake_id());
+    $cart2 = CartState::load(snowflake_id());
+    $item1 = ItemState::load(snowflake_id());
+    $item2 = ItemState::load(snowflake_id());
+
+    ItemRestocked::fire(item: $item1, quantity: 2);
+    ItemRestocked::fire(item: $item2, quantity: 2);
+
+    ItemAddedToCart::fire(cart: $cart1, item: $item1, quantity: 2);
+    ItemAddedToCart::fire(cart: $cart1, item: $item2, quantity: 2);
+
+    Date::setTestNow(now()->addSeconds(11));
+
+    ItemAddedToCart::fire(cart: $cart2, item: $item2, quantity: 2);
+
+    $this->assertThrows(fn () => CheckedOut::fire(cart: $cart1));
+
+    $this->assertEquals(2, $item1->available());
+    $this->assertEquals(0, collect($item1->activeHolds())->sum('quantity'));
+    $this->assertEquals(0, $item2->available());
+    $this->assertEquals(2, collect($item2->activeHolds())->sum('quantity'));
+});