SubscriptionActivationService: guard against merchant mismatch

tests/Feature/SubscriptionActivationServiceMerchantMismatchGuardTest.php

@@ -0,0 +1,78 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\Merchant;
+use App\Models\Plan;
+use App\Models\PlatformOrder;
+use App\Models\SiteSubscription;
+use App\Support\SubscriptionActivationService;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class SubscriptionActivationServiceMerchantMismatchGuardTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_activate_order_should_throw_when_subscription_merchant_mismatch(): void
+    {
+        $this->seed();
+
+        $merchantA = Merchant::query()->firstOrFail();
+        $merchantB = Merchant::query()->create([
+            'name' => '另一个演示站点',
+            'slug' => 'demo-merchant-b',
+            'status' => 'active',
+        ]);
+
+        $plan = Plan::query()->create([
+            'code' => 'mismatch_guard_test_plan',
+            'name' => '站点不一致护栏测试套餐',
+            'billing_cycle' => 'monthly',
+            'price' => 10,
+            'list_price' => 10,
+            'status' => 'active',
+            'sort' => 10,
+            'published_at' => now(),
+        ]);
+
+        $sub = SiteSubscription::query()->create([
+            'merchant_id' => $merchantA->id,
+            'plan_id' => $plan->id,
+            'status' => 'activated',
+            'source' => 'manual',
+            'subscription_no' => 'SUB_MERCHANT_MISMATCH_0001',
+            'plan_name' => $plan->name,
+            'billing_cycle' => $plan->billing_cycle,
+            'period_months' => 1,
+            'amount' => 10,
+            'starts_at' => now()->subDay(),
+            'ends_at' => now()->addDays(20),
+            'activated_at' => now()->subDay(),
+        ]);
+
+        $order = PlatformOrder::query()->create([
+            'merchant_id' => $merchantB->id,
+            'plan_id' => $plan->id,
+            'site_subscription_id' => $sub->id,
+            'order_no' => 'PO_MERCHANT_MISMATCH_0001',
+            'order_type' => 'renewal',
+            'status' => 'activated',
+            'payment_status' => 'paid',
+            'plan_name' => $plan->name,
+            'billing_cycle' => $plan->billing_cycle,
+            'period_months' => 1,
+            'quantity' => 1,
+            'payable_amount' => 10,
+            'paid_amount' => 10,
+            'placed_at' => now()->subMinutes(10),
+            'paid_at' => now()->subMinutes(5),
+            'activated_at' => now()->subMinutes(1),
+        ]);
+
+        $this->expectException(\InvalidArgumentException::class);
+
+        $service = new SubscriptionActivationService();
+        $service->activateOrder($order->id, 1);
+    }
+}