### Question:
NodeGroup { boolean isStandalone() { return memberMap.size() == 1 && memberMap.containsKey(selfId); } NodeGroup(NodeEndpoint endpoint);   NodeGroup(Collection<NodeEndpoint> endpoints, NodeId selfId);   }### Answer:
@Test public void testIsStandalone() { NodeGroup group = new NodeGroup(new NodeEndpoint("A", "localhost", 2333)); Assert.assertTrue(group.isStandalone()); group.addNode(new NodeEndpoint("B", "localhost", 2334), 10, 0, false); Assert.assertFalse(group.isStandalone()); }