--- /dev/null
+<?php
+
+namespace Drupal\KernelTests\Core\File;
+
+/**
+ * Tests the file_unmanaged_save_data() function.
+ *
+ * @group File
+ */
+class UnmanagedSaveDataTest extends FileTestBase {
+ /**
+ * Test the file_unmanaged_save_data() function.
+ */
+ public function testFileSaveData() {
+ $contents = $this->randomMachineName(8);
+ $this->setSetting('file_chmod_file', 0777);
+
+ // No filename.
+ $filepath = file_unmanaged_save_data($contents);
+ $this->assertTrue($filepath, 'Unnamed file saved correctly.');
+ $this->assertEqual(file_uri_scheme($filepath), file_default_scheme(), "File was placed in Drupal's files directory.");
+ $this->assertEqual($contents, file_get_contents($filepath), 'Contents of the file are correct.');
+
+ // Provide a filename.
+ $filepath = file_unmanaged_save_data($contents, 'public://asdf.txt', FILE_EXISTS_REPLACE);
+ $this->assertTrue($filepath, 'Unnamed file saved correctly.');
+ $this->assertEqual('asdf.txt', drupal_basename($filepath), 'File was named correctly.');
+ $this->assertEqual($contents, file_get_contents($filepath), 'Contents of the file are correct.');
+ $this->assertFilePermissions($filepath, 0777);
+ }
+
+}