### Question:
ChildrenManager { public ChildrenManager() { childServices = new HashMap<String, Date>(); } ChildrenManager(); static synchronized ChildrenManager getInstance(); synchronized List<String> getChildDSRs(); synchronized boolean addChildDSR(String identifier); synchronized void childLiveCheck();  }### Answer:
@Test public void testChildrenManager() { List<String> childs = manager.getChildDSRs(); if (!childs.isEmpty()) fail("Can not clean the childs collection!"); assertTrue(childs.isEmpty()); }