public function testIsBase64String()
 {
     $test_file_name = $this->getTestFileByBaseName('photo.jpg');
     $test_base64_file_name = $this->getTestFileByBaseName('photo.base64');
     $this->assertFalse(FileObject::isBase64String(file_get_contents($test_file_name)));
     $this->assertTrue(FileObject::isBase64String(base64_encode(file_get_contents($test_file_name))));
     $this->assertTrue(FileObject::isBase64String(file_get_contents($test_base64_file_name)));
 }