[TASK] Provide encryptionKey in unit tests

Since TYPO3 12.4.11 and 11.5.35 the encryptionKey is not initialized
in the default configuration, thus some unit tests will fail.

This commit ensures an encryptionKey is set for the unit tests.

Ports: #3959
Resolves: #3958

Tests/Unit/Domain/Variants/IdBuilderTest.php

@@ -25,32 +25,14 @@
  */
 class IdBuilderTest extends UnitTest
 {
-    /**
-     * @var string
-     */
-    protected $oldEncryptionKey;
-
-    protected function setUp(): void
-    {
-        $this->oldEncryptionKey = $GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'];
-        $GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'] = 'testkey';
-        parent::setUp();
-    }
-
-    protected function tearDown(): void
-    {
-        $GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'] = $this->oldEncryptionKey;
-        parent::tearDown();
-    }
-
     /**
      * @test
      */
     public function canBuildVariantId()
     {
         $build = new IdBuilder();
         $variantId = $build->buildFromTypeAndUid('pages', 4711);
-        self::assertSame('e99b3552a0451f1a2e7aca4ac06ccaba063393de/pages/4711', $variantId);
+        self::assertSame('c523304ea47711019595d2bb352b623d1db40427/pages/4711', $variantId);
     }
 
     /**

Tests/Unit/UnitTest.php

@@ -28,13 +28,25 @@
 abstract class UnitTest extends UnitTestCase
 {
     protected $resetSingletonInstances = true;
+    protected ?string $originalEncryptionKey;
 
     protected function setUp(): void
     {
         date_default_timezone_set('Europe/Berlin');
+        $this->originalEncryptionKey = $GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'] ?? null;
+        $GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'] = 'solr-tests-secret-encryption-key';
         parent::setUp();
     }
 
+    protected function tearDown(): void
+    {
+        unset($GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey']);
+        if ($this->originalEncryptionKey !== null) {
+            $GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'] = $this->originalEncryptionKey;
+        }
+        parent::tearDown();
+    }
+
     /**
      * Returns a mock class where every behaviour is mocked, just to full fill
      * the datatype and have the possibility to mock the behaviour.