public synchronized void lostNodeFound(Address address) {
    Preconditions.checkNotNull(address, "address should not be null");
    mLostNodes.remove(address);
    for (Runnable function : mChangeListeners) {
      function.run();
    }
  }
@Test
  public void lostNodeFound() {
    ConfigurationStore configStore = createConfigStore();

    configStore.handleNodeLost(mAddressOne);
    configStore.handleNodeLost(mAddressTwo);

    Map<Address, List<ConfigRecord>> confMap = configStore.getConfMap();
    assertFalse(confMap.containsKey(mAddressOne));
    assertFalse(confMap.containsKey(mAddressTwo));

    configStore.lostNodeFound(mAddressTwo);
    confMap = configStore.getConfMap();

    assertFalse(confMap.containsKey(mAddressOne));
    assertTrue(confMap.containsKey(mAddressTwo));
  }