code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.xpath.iterators;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.internal.utils.XpathIteratorUtil.findNode;
  
  import org.junit.jupiter.api.Test;
  
  import net.sf.saxon.om.NodeInfo;
  
  public class PrecedingIteratorTest {
  
      @Test
      public void testPrecedingNodes() {
          final NodeInfo startNode = findNode("SLIST");
  
          try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("PARAMETERS"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("METHOD_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("LCURLY"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("OBJBLOCK"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("CLASS_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("ANNOTATIONS"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("ANNOTATION_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("PACKAGE_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("ROOT"));
              assertWithMessage("Node should be null")
                      .that(iterator.next())
                      .isNull();
              assertWithMessage("Node should be null")
                      .that(iterator.next())
                      .isNull();
          }
      }
  
      @Test
      public void testNoParent() {
          final NodeInfo startNode = findNode("ROOT");
  
          try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
              assertWithMessage("Node should be null")
                      .that(iterator.next())
                      .isNull();
          }
      }
  
      @Test
      public void testReverseOrderOfDescendants() {
          final NodeInfo startNode = findNode("RCURLY");
  
          try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("METHOD_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("SLIST"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("PARAMETERS"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("LCURLY"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("OBJBLOCK"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("CLASS_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("ANNOTATIONS"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("ANNOTATION_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("PACKAGE_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("ROOT"));
              assertWithMessage("Node should be null")
                      .that(iterator.next())
                      .isNull();
          }
      }
  
      @Test
      public void testNoSibling() {
          final NodeInfo startNode = findNode("ANNOTATIONS");
  
          try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("PACKAGE_DEF"));
              assertWithMessage("Invalid node")
                      .that(iterator.next())
                      .isEqualTo(findNode("ROOT"));
              assertWithMessage("Node should be null")
                      .that(iterator.next())
                      .isNull();
          }
      }
  }
  