@Test
public void testGetParentMessageWithTheInReplyToHeader() throws Exception {

	Message message = Mockito.mock(Message.class);
	Mockito.when(
		message.getHeader("In-Reply-To")
	).thenReturn(
		new String[] {"<mb_message.10640.20646.1425017183884@gmail.com>"}
	);
	Assert.assertEquals(20646, MBMailUtil.getParentMessageId(message));
}