diff --git a/Tests/Unit/Resource/Collection/FileCollectionRegistryTest.php b/Tests/Unit/Resource/Collection/FileCollectionRegistryTest.php
index 2b5739c728..46deb0860e 100644
--- a/Tests/Unit/Resource/Collection/FileCollectionRegistryTest.php
+++ b/Tests/Unit/Resource/Collection/FileCollectionRegistryTest.php
@@ -18,7 +18,7 @@
 namespace TYPO3\CMS\Core\Tests\Unit\Resource\Collection;
 
 use TYPO3\CMS\Core\Resource\Collection\FileCollectionRegistry;
-use TYPO3\CMS\Core\Resource\Collection\StaticFileCollection;
+use TYPO3\CMS\Core\Tests\Unit\Resource\Collection\Fixtures\OtherTestingFileCollection;
 use TYPO3\CMS\Core\Tests\Unit\Resource\Collection\Fixtures\TestingFileCollection;
 use TYPO3\CMS\Core\Utility\StringUtility;
 use TYPO3\TestingFramework\Core\Unit\UnitTestCase;
@@ -70,7 +70,7 @@ public function registerFileCollectionClassThrowsExceptionIfTypeIsAlreadyRegiste
         $this->expectExceptionCode(1391295643);
         $subject = new FileCollectionRegistry();
         $className = TestingFileCollection::class;
-        $className2 = get_class($this->getMockForAbstractClass(StaticFileCollection::class));
+        $className2 = OtherTestingFileCollection::class;
         $subject->registerFileCollectionClass($className, 'foobar');
         $subject->registerFileCollectionClass($className2, 'foobar');
     }
@@ -81,7 +81,7 @@ public function registerFileCollectionClassThrowsExceptionIfTypeIsAlreadyRegiste
     public function registerFileCollectionClassOverridesExistingRegisteredFileCollectionClass(): void
     {
         $className = TestingFileCollection::class;
-        $className2 = get_class($this->getMockForAbstractClass(StaticFileCollection::class));
+        $className2 = OtherTestingFileCollection::class;
         $subject = new FileCollectionRegistry();
         $subject->registerFileCollectionClass($className, 'foobar');
         $subject->registerFileCollectionClass($className2, 'foobar', true);
diff --git a/Tests/Unit/Resource/Collection/Fixtures/OtherTestingFileCollection.php b/Tests/Unit/Resource/Collection/Fixtures/OtherTestingFileCollection.php
new file mode 100644
index 0000000000..95a2db1731
--- /dev/null
+++ b/Tests/Unit/Resource/Collection/Fixtures/OtherTestingFileCollection.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * 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!
+ */
+
+namespace TYPO3\CMS\Core\Tests\Unit\Resource\Collection\Fixtures;
+
+use TYPO3\CMS\Core\Resource\Collection\AbstractFileCollection;
+
+/**
+ * Testing subclass of the abstract class.
+ *
+ * This class exists because some tests need instances of different file collection classes.
+ */
+final class OtherTestingFileCollection extends AbstractFileCollection
+{
+    public function loadContents(): void
+    {
+        // stub
+    }
+}