CONV-259: Create CreditPack DTO

app/Data/Billing/CreditPackDto.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Data\Billing;
+
+final readonly class CreditPackDto
+{
+    public function __construct(
+        public string $key,
+        public string $label,
+        public int $credits,
+        public string $stripePriceId,
+        public string $description,
+    ) {}
+
+    public static function fromConfig(string $key, array $config): self
+    {
+        $required = ['label', 'credits', 'stripe_price_id', 'description'];
+
+        foreach ($required as $field) {
+            if (! array_key_exists($field, $config)) {
+                throw new \InvalidArgumentException("Missing required credit pack config key: {$field}");
+            }
+        }
+
+        return new self(
+            key: $key,
+            label: $config['label'],
+            credits: $config['credits'],
+            stripePriceId: $config['stripe_price_id'],
+            description: $config['description'],
+        );
+    }
+}

tests/Unit/Billing/CreditPackDtoTest.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Data\Billing\CreditPackDto;
+
+it('creates credit pack dto from config array', function () {
+    $dto = CreditPackDto::fromConfig('small', [
+        'label' => '500 Credits',
+        'credits' => 500,
+        'stripe_price_id' => 'price_small',
+        'description' => 'Good for occasional conversions.',
+    ]);
+
+    expect($dto->key)->toBe('small');
+    expect($dto->label)->toBe('500 Credits');
+    expect($dto->credits)->toBe(500);
+    expect($dto->stripePriceId)->toBe('price_small');
+    expect($dto->description)->toBe('Good for occasional conversions.');
+});
+
+it('throws on missing required config keys', function () {
+    CreditPackDto::fromConfig('small', [
+        'label' => '500 Credits',
+        'credits' => 500,
+    ]);
+})->throws(InvalidArgumentException::class);