Added placeholder users; Better exception handling; Enhanced local setup

tests/Unit/Service/UserServiceTest.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Service;
+
+use App\Models\Organization;
+use App\Models\TimeEntry;
+use App\Models\User;
+use App\Service\UserService;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class UserServiceTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_assign_organization_entities_to_different_user(): void
+    {
+        // Arrange
+        $organization = Organization::factory()->create();
+        $otherUser = User::factory()->create();
+        $fromUser = User::factory()->create();
+        $toUser = User::factory()->create();
+        TimeEntry::factory()->forOrganization($organization)->forUser($otherUser)->createMany(3);
+        TimeEntry::factory()->forOrganization($organization)->forUser($fromUser)->createMany(3);
+
+        // Act
+        $userService = app(UserService::class);
+        $userService->assignOrganizationEntitiesToDifferentUser($organization, $fromUser, $toUser);
+
+        // Assert
+        $this->assertSame(3, TimeEntry::query()->whereBelongsTo($toUser, 'user')->count());
+        $this->assertSame(3, TimeEntry::query()->whereBelongsTo($otherUser, 'user')->count());
+        $this->assertSame(0, TimeEntry::query()->whereBelongsTo($fromUser, 'user')->count());
+    }
+}