[TASK] Make getInstanceIdentifier() and getInstancePath() non-static for overridability

Convert protected static methods to protected instance methods and mark as @internal.
This allows subclasses to override these methods for proper test isolation in parallel
execution (Paratest), without making them part of the public API.

Instead of using static:: binding, use $this-> for natural method overriding.
Solves the need for test isolation in single-test-level parallelization while
signaling that these are internal implementation details.

Relates to: #708

Author: dkd-kaehm

Classes/Core/Functional/FunctionalTestCase.php

@@ -284,8 +284,8 @@ protected function setUp(): void
             self::markTestSkipped('Functional tests must be called through phpunit on CLI');
         }
 
-        $this->identifier = self::getInstanceIdentifier();
-        $this->instancePath = self::getInstancePath();
+        $this->identifier = $this->getInstanceIdentifier();
+        $this->instancePath = $this->getInstancePath();
         putenv('TYPO3_PATH_ROOT=' . $this->instancePath);
         putenv('TYPO3_PATH_APP=' . $this->instancePath);
 
@@ -1100,19 +1100,21 @@ protected function withDatabaseSnapshot(?callable $createCallback = null, ?calla
     /**
      * Uses a 7 char long hash of class name as identifier.
      *
+     * @internal
      * @return non-empty-string
      */
-    protected static function getInstanceIdentifier(): string
+    protected function getInstanceIdentifier(): string
     {
         return substr(sha1(static::class), 0, 7);
     }
 
     /**
+     * @internal
      * @return non-empty-string
      */
-    protected static function getInstancePath(): string
+    protected function getInstancePath(): string
     {
-        $identifier = self::getInstanceIdentifier();
+        $identifier = $this->getInstanceIdentifier();
         return ORIGINAL_ROOT . 'typo3temp/var/tests/functional-' . $identifier;
     }
 }

Tests/Unit/Core/Functional/FunctionalTestCaseTest.php

@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TYPO3\TestingFramework\Tests\Unit\Core\Functional;
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+use PHPUnit\Framework\Attributes\Test;
+use TYPO3\TestingFramework\Core\Functional\FunctionalTestCase;
+use TYPO3\TestingFramework\Core\Unit\UnitTestCase;
+
+class FunctionalTestCaseTest extends UnitTestCase
+{
+    #[Test]
+    public function GetInstanceIdentifierAndGetInstancePathCanBeOverridden(): void
+    {
+        // Define ORIGINAL_ROOT constant if not already defined (needed by setUp)
+        if (!defined('ORIGINAL_ROOT')) {
+            define('ORIGINAL_ROOT', dirname(__DIR__, 5));
+        }
+
+        // Anonymous subclass to test method overrides in setUp() method calling:
+        //   $this->identifier = $this->getInstanceIdentifier();
+        $testInstance = new class ('overriddenGetInstanceIdentifierAndGetInstancePathMethods') extends FunctionalTestCase {
+            protected function getInstanceIdentifier(): string
+            {
+                return 'test_identifier_from_subclass_xyz';
+            }
+
+            protected function getInstancePath(): string
+            {
+                return parent::getInstancePath() . '/suffix_from_subclass_xyz';
+            }
+
+            public function getIdentifier(): string
+            {
+                return $this->identifier;
+            }
+
+            public function getInstancePathProperty(): string
+            {
+                return $this->instancePath;
+            }
+
+            public function setUp(): void
+            {
+                try {
+                    parent::setUp();
+                } catch (\Throwable) {
+
+                }
+            }
+        };
+        $testInstance->setUp();
+
+        // The key assertions: values must contain the subclass overrides,
+        // proving that methods can be properly overridden in subclasses
+        self::assertSame('test_identifier_from_subclass_xyz', $testInstance->getIdentifier());
+        self::assertStringEndsWith('/suffix_from_subclass_xyz', $testInstance->getInstancePathProperty());
+    }
+}