	@Test
	public void test() throws ServletException, IOException {

		// given
		HttpServletResponse resp = Mockito.mock(HttpServletResponse.class);
		StringWriter sw = new StringWriter();
		Mockito.when(resp.getWriter()).thenReturn(new PrintWriter(sw));

		// when
		new PingServlet().doGet(null, resp);

		// then
		String s = sw.toString();
		assertNotNull(s);
		long parsedTimestamp = Long.parseLong(s);
		assertTrue(new Date().getTime() >= parsedTimestamp);
	}