ObjWithString example

'expected_message' => "'foo' value is '1.123000'",
      ],
      'NULL' => [
        'value' => NULL,
        'expected_message' => "'foo' value is 'NULL'",
      ],
      'boolean' => [
        'value' => TRUE,
        'expected_message' => "'foo' value is 'true'",
      ],
      'object_with_to_String' => [
        'value' => new ObjWithString(),
        'expected_message' => "'foo' value is Drupal\Tests\migrate\Unit\process\ObjWithString:\n'a test string'",
      ],
      'object_no_to_string' => [
        'value' => $object,
        'expected_message' => "Unable to log the value for 'foo'",
      ],
      'simple_xml' => [
        'value' => new \SimpleXMLElement($xml_str),
        'expected_message' => "'foo' value is SimpleXMLElement:\n'\n \n'",
      ],
    ];
  }