@Test
public void testChangeSessionId() {

  HttpServletRequest wrappedSimple = mock(HttpServletRequest.class);
  HttpRequestWrapper req = new HttpRequestWrapper(wrappedSimple, servletContext);
  RepositoryBackedHttpSession session = mock(RepositoryBackedHttpSession.class);
  when(sessionManager.getSession(req, false, null)).thenReturn(session);
  when(session.getId()).thenReturn(SESSION_ID);
  String id = req.changeSessionId();
  assertEquals(SESSION_ID, id);
  verify(sessionManager).switchSessionId(session);
  verify(session).getId();
}