Define test classes as final

tests/Feature/BooksTest.php

@@ -4,7 +4,7 @@ namespace Tests\Feature;
 
 use Tests\TestCase;
 
-class BooksTest extends TestCase
+final class BooksTest extends TestCase
 {
     /**
      * @throws \DariusIII\ItunesApi\Exceptions\InvalidProviderException

tests/Feature/SettingsTest.php

@@ -4,7 +4,7 @@ namespace Tests\Feature;
 
 use Tests\TestCase;
 
-class SettingsTest extends TestCase
+final class SettingsTest extends TestCase
 {
     public function testSettingValue(): void
     {

tests/Install/InstallTest.php

@@ -18,7 +18,7 @@ require_once \dirname(__DIR__, 2).DIRECTORY_SEPARATOR.'bootstrap/autoload.php';
 /**
  * Class InstallTest.
  */
-class InstallTest extends \PHPUnit\Framework\TestCase
+final class InstallTest extends \PHPUnit\Framework\TestCase
 {
     public function testFullInstall(): void
     {

tests/Unit/ExampleTest.php

@@ -4,7 +4,7 @@ namespace Tests\Unit;
 
 use PHPUnit\Framework\TestCase;
 
-class ExampleTest extends TestCase
+final class ExampleTest extends TestCase
 {
     /**
      * A basic test example.