Step 00 — Squelette + intégration naïve

3 Bounded Contexts (Sales, Invoicing, LegacyFulfillment) avec :
- Domaines complets (agrégats, VOs, événements, invariants)
- Couche application (commands, queries, ports)
- Infrastructure in-memory (repos, gateway fake)
- Controllers HTTP Symfony
- Couplage naïf synchrone entre BC via NaiveSalesEventPublisher
- 20 tests unitaires et d'intégration passants

tests/Unit/Invoicing/Domain/InvoiceTest.php

@@ -0,0 +1,97 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Tests\Unit\Invoicing\Domain;
+
+use MiniShop\Invoicing\Domain\Event\InvoiceIssued;
+use MiniShop\Invoicing\Domain\Model\BillingParty;
+use MiniShop\Invoicing\Domain\Model\Invoice;
+use MiniShop\Invoicing\Domain\Model\InvoiceId;
+use MiniShop\Invoicing\Domain\Model\InvoiceLine;
+use MiniShop\Invoicing\Domain\Model\InvoiceStatus;
+use MiniShop\Invoicing\Domain\Model\TaxRate;
+use PHPUnit\Framework\TestCase;
+
+final class InvoiceTest extends TestCase
+{
+    public function test_issue_invoice_for_external_order(): void
+    {
+        $invoice = $this->issueInvoice();
+
+        self::assertSame(InvoiceStatus::Issued, $invoice->status());
+        self::assertSame('ext-order-1', $invoice->externalOrderId);
+        self::assertCount(1, $invoice->lines());
+    }
+
+    public function test_issue_invoice_records_event(): void
+    {
+        $invoice = $this->issueInvoice();
+
+        $events = $invoice->releaseEvents();
+        self::assertCount(1, $events);
+        self::assertInstanceOf(InvoiceIssued::class, $events[0]);
+    }
+
+    public function test_invoice_without_lines_throws(): void
+    {
+        $this->expectException(\DomainException::class);
+
+        Invoice::issueForExternalOrder(
+            InvoiceId::fromString('inv-1'),
+            'INV-000001',
+            'ext-order-1',
+            new BillingParty('Acme', '1 Rue Test'),
+            [],
+            new \DateTimeImmutable(),
+        );
+    }
+
+    public function test_total_coherent_with_lines(): void
+    {
+        $invoice = Invoice::issueForExternalOrder(
+            InvoiceId::fromString('inv-1'),
+            'INV-000001',
+            'ext-order-1',
+            new BillingParty('Acme', '1 Rue Test'),
+            [
+                new InvoiceLine('Widget', 2, 1000, 'EUR', TaxRate::standard()),
+                new InvoiceLine('Gadget', 1, 2500, 'EUR', TaxRate::standard()),
+            ],
+            new \DateTimeImmutable(),
+        );
+
+        self::assertSame(4500, $invoice->totalExclTax());
+        self::assertSame(5400, $invoice->totalInclTax());
+    }
+
+    public function test_mark_as_sent(): void
+    {
+        $invoice = $this->issueInvoice();
+
+        $invoice->markAsSent();
+
+        self::assertSame(InvoiceStatus::Sent, $invoice->status());
+    }
+
+    public function test_mark_as_sent_twice_throws(): void
+    {
+        $this->expectException(\DomainException::class);
+
+        $invoice = $this->issueInvoice();
+        $invoice->markAsSent();
+        $invoice->markAsSent();
+    }
+
+    private function issueInvoice(): Invoice
+    {
+        return Invoice::issueForExternalOrder(
+            InvoiceId::fromString('inv-1'),
+            'INV-000001',
+            'ext-order-1',
+            new BillingParty('Acme', '1 Rue Test'),
+            [new InvoiceLine('Widget', 2, 1500, 'EUR', TaxRate::standard())],
+            new \DateTimeImmutable(),
+        );
+    }
+}