diff --git a/tests/Unit/Libraries/Cms/Cache/Storage/FileStorageTest.php b/tests/Unit/Libraries/Cms/Cache/Storage/FileStorageTest.php
new file mode 100644
index 0000000000000..c13c1720bd7c9
--- /dev/null
+++ b/tests/Unit/Libraries/Cms/Cache/Storage/FileStorageTest.php
@@ -0,0 +1,98 @@
+<?php
+
+/**
+ * @package    Joomla.UnitTest
+ * @subpackage Cache
+ */
+
+namespace Joomla\Tests\Unit\Libraries\Cms\Cache\Storage;
+
+use Joomla\CMS\Cache\Storage\FileStorage;
+use Joomla\CMS\Factory;
+use Joomla\CMS\Application\CMSApplicationInterface;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test class for FileStorage.
+ */
+class FileStorageTest extends TestCase
+{
+    private $object;
+    private $cacheDir;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $app = $this->createMock(CMSApplicationInterface::class);
+
+        $app->method('get')->willReturnCallback(function ($key, $default = null) {
+            if ($key === 'cachetime') {
+                return 15;
+            }
+            if ($key === 'secret') {
+                return 'test_secret_key_for_unit_tests';
+            }
+            return $default;
+        });
+
+        if (method_exists(Factory::class, 'setApplication')) {
+            Factory::setApplication($app);
+        } else {
+            $reflection = new \ReflectionClass(Factory::class);
+            $property = $reflection->getProperty('application');
+            $property->setAccessible(true);
+            $property->setValue(null, $app);
+        }
+
+        $this->cacheDir = sys_get_temp_dir() . '/joomla_test_cache_' . uniqid();
+        mkdir($this->cacheDir, 0755, true);
+
+        if (!defined('JPATH_CACHE')) {
+            define('JPATH_CACHE', $this->cacheDir);
+        }
+
+        $this->object = new FileStorage(['cache_dir' => $this->cacheDir]);
+
+        $reflection = new \ReflectionClass($this->object);
+        $property = $reflection->getProperty('_root');
+        $property->setAccessible(true);
+        $property->setValue($this->object, $this->cacheDir);
+    }
+
+    protected function tearDown(): void
+    {
+        $files = glob($this->cacheDir . '/*');
+        if ($files) {
+            foreach ($files as $file) {
+                if (is_file($file)) {
+                    unlink($file);
+                }
+            }
+        }
+
+        if (is_dir($this->cacheDir)) {
+            rmdir($this->cacheDir);
+        }
+
+        parent::tearDown();
+    }
+
+    public function testStoreUsesAtomicWriteAndCleansUpTempFiles()
+    {
+        $id    = 'test_atomic_write';
+        $group = 'test_group';
+        $data  = 'This is test cache data that should be written atomically.';
+
+        $result = $this->object->store($id, $group, $data);
+
+        $this->assertTrue($result, 'The store operation should return true on success.');
+
+        $retrievedData = $this->object->get($id, $group);
+        $this->assertEquals($data, $retrievedData, 'Retrieved cache data should match the stored data.');
+
+        $files = glob($this->cacheDir . '/' . $group . '/*.tmp');
+
+        $this->assertEmpty($files, 'No temporary .tmp files should be left behind after a successful store.');
+    }
+}