refactor: centralize receipt total logic on PlatformOrder

tests/Unit/PlatformOrderReceiptTotalTest.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace Tests\Unit;
+
+use App\Models\Merchant;
+use App\Models\Plan;
+use App\Models\PlatformOrder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class PlatformOrderReceiptTotalTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_receipt_total_can_fallback_to_receipts_sum_when_payment_summary_missing(): void
+    {
+        $merchant = Merchant::query()->create([
+            'name' => '单测站点_receipt',
+            'slug' => 'unit-test-merchant-receipt',
+            'status' => 'active',
+        ]);
+
+        $plan = Plan::query()->create([
+            'code' => 'unit_test_plan_receipt_total',
+            'name' => '单测套餐_receipt',
+            'billing_cycle' => 'monthly',
+            'price' => 10,
+            'list_price' => 10,
+            'status' => 'active',
+            'sort' => 10,
+            'published_at' => now(),
+        ]);
+
+        $order = PlatformOrder::query()->create([
+            'merchant_id' => $merchant->id,
+            'plan_id' => $plan->id,
+            'order_no' => 'PO_UNIT_RECEIPT_TOTAL_0001',
+            'order_type' => 'subscription',
+            'status' => 'activated',
+            'payment_status' => 'paid',
+            'plan_name' => 'Unit Test Plan',
+            'billing_cycle' => 'monthly',
+            'period_months' => 1,
+            'quantity' => 1,
+            'payable_amount' => 10,
+            'paid_amount' => 10,
+            'placed_at' => now(),
+            'meta' => [
+                'payment_receipts' => [
+                    ['amount' => 3.25],
+                    ['amount' => 1.15],
+                ],
+            ],
+        ]);
+
+        $this->assertEquals(4.40, $order->receiptTotal());
+    }
+}