// tests the getList method after adding clients
  @Test
  public void testGetList() throws IOException {
    serverNodes.add(channel1);
    serverNodes.add(channel2);
    serverNodes.add(channel3);

    String output = serverNodes.getList();
    assertEquals(output, "ServerNodes: 1 2 3");
  }
  // tests the getList method on an empty list that was once filled
  @Test
  public void testEmptyListAfterRemovals() throws IOException {
    serverNodes.add(channel1);
    serverNodes.add(channel2);
    serverNodes.add(channel3);

    serverNodes.remove(channel3);
    serverNodes.remove(channel2);
    serverNodes.remove(channel1);

    String output = serverNodes.getList();
    assertEquals(output, "ServerNodes: ");
  }
 // tests the getList method on an empty list
 @Test
 public void testEmptyList() throws IOException {
   String output = serverNodes.getList();
   assertEquals(output, "ServerNodes: ");
 }