@Test
public void testNonExistingNode() throws Exception {

  Node n;
  n = CLUSTER.chooseRandomWithStorageType(
      "/l100", null, null, StorageType.DISK);
  assertNull(n);
  n = CLUSTER.chooseRandomWithStorageType(
      "/l100/d100", null, null, StorageType.DISK);
  assertNull(n);
  n = CLUSTER.chooseRandomWithStorageType(
      "/l100/d100/r100", null, null, StorageType.DISK);
  assertNull(n);
}