FileSaveDataTest.php

<?php

namespace Drupal\KernelTests\Core\File;

use Drupal\Core\File\FileSystemInterface;

/**
 * Tests the file_unmanaged_save_data() function.
 *
 * @group File
 */
class FileSaveDataTest extends FileTestBase {
    
    /**
     * Tests the file_unmanaged_save_data() function.
     */
    public function testFileSaveData() {
        $contents = $this->randomMachineName(8);
        $this->setSetting('file_chmod_file', 0777);
        // No filename.
        
        /** @var \Drupal\Core\File\FileSystemInterface $file_system */
        $file_system = \Drupal::service('file_system');
        // Provide a filename.
        $filepath = $file_system->saveData($contents, 'public://asdf.txt', FileSystemInterface::EXISTS_REPLACE);
        $this->assertNotFalse($filepath, 'Unnamed file saved correctly.');
        $this->assertEquals('asdf.txt', \Drupal::service('file_system')->basename($filepath), 'File was named correctly.');
        $this->assertEquals($contents, file_get_contents($filepath), 'Contents of the file are correct.');
        $this->assertFilePermissions($filepath, 0777);
    }

}