### Question:
MailUtils { public static Properties getMailProperties( Properties properties ) { return filter( properties, MAIL_PROP_PREFIX ); }  static Properties getMailProperties( Properties properties ); void sendMail( Properties props, String to, String from, String subject, String plainText,
                          String htmlText ); void sendHtmlMail( Properties props, String to, String from, String subject, String html );  }### Answer:
@Test public void propertiesExtraction() { props.put( "some.other.prop", "foo" ); assertEquals( 5, props.size() ); assertEquals( 4, MailUtils.getMailProperties( props ).size() ); }