feat: add the booking domain layer

tests/Entity/BookingTest.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Entity;
+
+use App\Entity\Booking;
+use App\Entity\Resource;
+use App\Entity\ResourceType;
+use App\Entity\User;
+use PHPUnit\Framework\TestCase;
+
+class BookingTest extends TestCase
+{
+    public function testTheDateIsNormalisedToMidnightSoTheUniqueConstraintCannotBeSidestepped(): void
+    {
+        $booking = new Booking(
+            new User('[email protected]', 'A'),
+            new Resource(ResourceType::DESK, 'D1'),
+            new \DateTimeImmutable('2026-09-13 14:37:11'),
+        );
+
+        self::assertSame('2026-09-13 00:00:00', $booking->getDate()->format('Y-m-d H:i:s'));
+    }
+}

tests/Entity/UserTest.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Entity;
+
+use App\Entity\User;
+use PHPUnit\Framework\TestCase;
+
+class UserTest extends TestCase
+{
+    public function testEveryUserGetsRoleUserWithoutItBeingStored(): void
+    {
+        self::assertSame(['ROLE_USER'], (new User('[email protected]', 'A'))->getRoles());
+    }
+
+    public function testRoleUserIsNotDuplicatedWhenAlreadyGranted(): void
+    {
+        $user = new User('[email protected]', 'A');
+        $user->setRoles(['ROLE_USER', 'ROLE_EMPLOYEE']);
+
+        self::assertSame(['ROLE_USER', 'ROLE_EMPLOYEE'], $user->getRoles());
+    }
+
+    public function testTheEmailIsTheSecurityIdentifier(): void
+    {
+        self::assertSame('[email protected]', (new User('[email protected]', 'A'))->getUserIdentifier());
+    }
+}