feat: implement user registration functionality with validation and response handling

tests/Feature/Auth/RegisterControllerTest.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace Tests\Feature\Auth;
+
+use App\Domains\Auth\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class RegisterControllerTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_it_registers_a_user(): void
+    {
+        $response = $this->postJson('/api/register', [
+            'nombre_apellido' => 'Ada Lovelace',
+            'email' => 'ada@example.com',
+            'password' => 'secret123',
+            'password_confirmation' => 'secret123',
+        ]);
+
+        $response
+            ->assertCreated()
+            ->assertJsonPath('message', 'Usuario registrado correctamente.')
+            ->assertJsonPath('data.nombre_apellido', 'Ada Lovelace')
+            ->assertJsonPath('data.email', 'ada@example.com');
+
+        $this->assertDatabaseHas('users', [
+            'nombre_apellido' => 'Ada Lovelace',
+            'email' => 'ada@example.com',
+        ]);
+
+        $user = User::query()->where('email', 'ada@example.com')->firstOrFail();
+
+        $this->assertNotSame('secret123', $user->password);
+    }
+
+    public function test_it_validates_required_fields_and_unique_email(): void
+    {
+        User::factory()->create([
+            'nombre_apellido' => 'Existing User',
+            'email' => 'existing@example.com',
+        ]);
+
+        $response = $this->postJson('/api/register', [
+            'nombre_apellido' => '',
+            'email' => 'existing@example.com',
+            'password' => 'secret123',
+            'password_confirmation' => 'different-secret',
+        ]);
+
+        $response->assertUnprocessable()->assertJsonValidationErrors([
+            'nombre_apellido',
+            'email',
+            'password',
+        ]);
+    }
+}