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.utils;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsClassHasPrivateConstructor;
  
  import java.lang.reflect.Field;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.TreeMap;
  
  import org.junit.jupiter.api.Test;
  
  import com.puppycrawl.tools.checkstyle.DetailAstImpl;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  
  public class TokenUtilTest {
  
      @Test
      public void testIsProperUtilsClass() throws ReflectiveOperationException {
          assertWithMessage("Constructor is not private")
                  .that(isUtilsClassHasPrivateConstructor(TokenUtil.class))
                  .isTrue();
      }
  
      @Test
      public void testGetIntFromAccessibleField() throws NoSuchFieldException {
          final Field field = Integer.class.getField("MAX_VALUE");
          final int maxValue = TokenUtil.getIntFromField(field, 0);
  
          assertWithMessage("Invalid getIntFromField result")
              .that(maxValue)
              .isEqualTo(Integer.MAX_VALUE);
      }
  
      @Test
      public void testGetIntFromInaccessibleField() throws NoSuchFieldException {
          final Field field = Integer.class.getDeclaredField("value");
  
          try {
              TokenUtil.getIntFromField(field, 0);
              assertWithMessage("IllegalStateException is expected").fail();
          }
          catch (IllegalStateException expected) {
              // The exception message may vary depending on the version of the JDK.
              // It will definitely contain the TokenUtil class name and the Integer class name.
              final String message = expected.getMessage();
              assertWithMessage("Invalid exception message: " + message)
                      .that(message.startsWith("java.lang.IllegalAccessException: ")
                              && message.contains("com.puppycrawl.tools.checkstyle.utils.TokenUtil")
                              && message.contains("access a member of class java.lang.Integer"))
                      .isTrue();
          }
      }
  
      @Test
      public void testNameToValueMapFromPublicIntFields() {
          final Map<String, Integer> actualMap =
              TokenUtil.nameToValueMapFromPublicIntFields(Integer.class);
          final Map<String, Integer> expectedMap = new TreeMap<>();
          expectedMap.put("BYTES", Integer.BYTES);
          expectedMap.put("SIZE", Integer.SIZE);
          expectedMap.put("MAX_VALUE", Integer.MAX_VALUE);
          expectedMap.put("MIN_VALUE", Integer.MIN_VALUE);
  
          assertWithMessage("Unexpected name to value map")
              .that(actualMap)
              .isEqualTo(expectedMap);
      }
  
      @Test
      public void testInvertMap() {
          final Map<String, Integer> map = new TreeMap<>();
          map.put("ZERO", 0);
          map.put("ONE", 1);
          map.put("TWO", 2);
          map.put("NEGATIVE", -1);
  
          final Map<Integer, String> invertedMap = TokenUtil.invertMap(map);
  
          assertWithMessage("Key set of 'map' and values of 'invertedMap' should be the same.")
                  .that(invertedMap.values())
                  .containsExactlyElementsIn(map.keySet());
          assertWithMessage("Values of 'map' and key set of 'invertedMap' should be the same.")
                  .that(invertedMap.keySet())
                  .containsExactlyElementsIn(map.values());
      }
  
      @Test
      public void testTokenValueIncorrect() throws IllegalAccessException {
          int maxId = 0;
          final Field[] fields = TokenTypes.class.getDeclaredFields();
          for (final Field field : fields) {
              // Only process the int declarations.
              if (field.getType() != Integer.TYPE) {
                  continue;
              }
  
              final String name = field.getName();
              final int id = field.getInt(name);
              if (id > maxId) {
                  maxId = id;
              }
          }
  
          final int nextAfterMaxId = maxId + 1;
          try {
              TokenUtil.getTokenName(nextAfterMaxId);
              assertWithMessage("IllegalArgumentException is expected").fail();
          }
          catch (IllegalArgumentException expectedException) {
              assertWithMessage("Invalid exception message")
                  .that(expectedException.getMessage())
                  .isEqualTo("unknown TokenTypes id '" + nextAfterMaxId + "'");
          }
      }
  
      @Test
      public void testTokenValueCorrect() throws IllegalAccessException {
          final Field[] fields = TokenTypes.class.getDeclaredFields();
          for (final Field field : fields) {
              // Only process the int declarations.
              if (field.getType() != Integer.TYPE) {
                  continue;
              }
  
              final String name = field.getName();
              final int id = field.getInt(name);
  
              assertWithMessage("Invalid token name")
                  .that(TokenUtil.getTokenName(id))
                  .isEqualTo(name);
          }
      }
  
      @Test
      public void testTokenValueIncorrect2() {
          final int id = 0;
          try {
              TokenUtil.getTokenName(id);
              assertWithMessage("IllegalArgumentException is expected").fail();
          }
          catch (IllegalArgumentException expected) {
              assertWithMessage("Invalid exception message")
                  .that(expected.getMessage())
                  .isEqualTo("unknown TokenTypes id '" + id + "'");
          }
      }
  
      @Test
      public void testTokenIdIncorrect() {
          final String id = "NON_EXISTENT_VALUE";
          try {
              TokenUtil.getTokenId(id);
              assertWithMessage("IllegalArgumentException is expected").fail();
          }
          catch (IllegalArgumentException expected) {
              assertWithMessage("Invalid exception message")
                  .that(expected.getMessage())
                  .isEqualTo("unknown TokenTypes value '" + id + "'");
          }
      }
  
      @Test
      public void testShortDescriptionIncorrect() {
          final String id = "NON_EXISTENT_VALUE";
          try {
              TokenUtil.getShortDescription(id);
              assertWithMessage("IllegalArgumentException is expected").fail();
          }
          catch (IllegalArgumentException expected) {
              assertWithMessage("Invalid exception message")
                  .that(expected.getMessage())
                  .isEqualTo("unknown TokenTypes value '" + id + "'");
          }
      }
  
      @Test
      public void testIsCommentType() {
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isCommentType(TokenTypes.SINGLE_LINE_COMMENT))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isCommentType(TokenTypes.BLOCK_COMMENT_BEGIN))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isCommentType(TokenTypes.BLOCK_COMMENT_END))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isCommentType(TokenTypes.COMMENT_CONTENT))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isCommentType("COMMENT_CONTENT"))
                  .isTrue();
          assertWithMessage("Should return false when invalid type passed")
                  .that(TokenUtil.isCommentType(TokenTypes.CLASS_DEF))
                  .isFalse();
          assertWithMessage("Should return false when invalid type passed")
                  .that(TokenUtil.isCommentType("CLASS_DEF"))
                  .isFalse();
      }
  
      @Test
      public void testGetTokenTypesTotalNumber() {
          final int tokenTypesTotalNumber = TokenUtil.getTokenTypesTotalNumber();
  
          assertWithMessage("Invalid token total number")
              .that(tokenTypesTotalNumber)
              .isEqualTo(188);
      }
  
      @Test
      public void testGetAllTokenIds() {
          final int[] allTokenIds = TokenUtil.getAllTokenIds();
          final int sum = Arrays.stream(allTokenIds).sum();
  
          assertWithMessage("Invalid token length")
              .that(allTokenIds.length)
              .isEqualTo(188);
          assertWithMessage("invalid sum")
              .that(sum)
              .isEqualTo(19595);
      }
  
      @Test
      public void testGetTokenNameWithGreatestPossibleId() {
          final int id = TokenTypes.COMMENT_CONTENT;
          final String tokenName = TokenUtil.getTokenName(id);
  
          assertWithMessage("Invalid token name")
              .that(tokenName)
              .isEqualTo("COMMENT_CONTENT");
      }
  
      @Test
      public void testCorrectBehaviourOfGetTokenId() {
          final String id = "COMPILATION_UNIT";
  
          assertWithMessage("Invalid token id")
              .that(TokenUtil.getTokenId(id))
              .isEqualTo(TokenTypes.COMPILATION_UNIT);
      }
  
      @Test
      public void testCorrectBehaviourOfShortDescription() {
          final String id = "COMPILATION_UNIT";
          final String shortDescription = TokenUtil.getShortDescription(id);
  
          assertWithMessage("Invalid short description")
              .that(shortDescription)
              .isEqualTo("This is the root node for the source file.");
      }
  
      @Test
      public void testFindFirstTokenByPredicate() {
          final DetailAstImpl astForTest = new DetailAstImpl();
          final DetailAstImpl child = new DetailAstImpl();
          final DetailAstImpl firstSibling = new DetailAstImpl();
          final DetailAstImpl secondSibling = new DetailAstImpl();
          final DetailAstImpl thirdSibling = new DetailAstImpl();
          firstSibling.setText("first");
          secondSibling.setText("second");
          thirdSibling.setText("third");
          secondSibling.setNextSibling(thirdSibling);
          firstSibling.setNextSibling(secondSibling);
          child.setNextSibling(firstSibling);
          astForTest.setFirstChild(child);
          final Optional<DetailAST> result = TokenUtil.findFirstTokenByPredicate(astForTest,
              ast -> "second".equals(ast.getText()));
  
          assertWithMessage("Invalid second sibling")
              .that(result.orElse(null))
              .isEqualTo(secondSibling);
      }
  
      @Test
      public void testForEachChild() {
          final DetailAstImpl astForTest = new DetailAstImpl();
          final DetailAstImpl child = new DetailAstImpl();
          final DetailAstImpl firstSibling = new DetailAstImpl();
          final DetailAstImpl secondSibling = new DetailAstImpl();
          final DetailAstImpl thirdSibling = new DetailAstImpl();
          firstSibling.setType(TokenTypes.DOT);
          secondSibling.setType(TokenTypes.CLASS_DEF);
          thirdSibling.setType(TokenTypes.IDENT);
          secondSibling.setNextSibling(thirdSibling);
          firstSibling.setNextSibling(secondSibling);
          child.setNextSibling(firstSibling);
          astForTest.setFirstChild(child);
          final List<DetailAST> children = new ArrayList<>();
          TokenUtil.forEachChild(astForTest, TokenTypes.CLASS_DEF, children::add);
          final DetailAST firstChild = children.get(0);
  
          assertWithMessage("Must be one match")
              .that(children)
              .hasSize(1);
          assertWithMessage("Mismatched child node")
              .that(firstChild)
              .isEqualTo(secondSibling);
      }
  
      @Test
      public void testIsTypeDeclaration() {
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isTypeDeclaration(TokenTypes.CLASS_DEF))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isTypeDeclaration(TokenTypes.INTERFACE_DEF))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isTypeDeclaration(TokenTypes.ANNOTATION_DEF))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isTypeDeclaration(TokenTypes.ENUM_DEF))
                  .isTrue();
          assertWithMessage("Should return true when valid type passed")
                  .that(TokenUtil.isTypeDeclaration(TokenTypes.RECORD_DEF))
                  .isTrue();
      }
  
      @Test
      public void testIsOfTypeTrue() {
          final int type = TokenTypes.LITERAL_CATCH;
          final DetailAstImpl astForTest = new DetailAstImpl();
          astForTest.setType(type);
          final boolean result1 = TokenUtil.isOfType(type, TokenTypes.LITERAL_FOR,
                                  TokenTypes.LITERAL_IF, TokenTypes.LITERAL_CATCH);
          final boolean result2 = TokenUtil.isOfType(astForTest, TokenTypes.LITERAL_FOR,
                                  TokenTypes.LITERAL_IF, TokenTypes.LITERAL_CATCH);
  
          assertWithMessage("Token type did not match")
                  .that(result1)
                  .isTrue();
          assertWithMessage("Token type did not match")
                  .that(result2)
                  .isTrue();
      }
  
      @Test
      public void testIsOfTypeFalse() {
          final int type = TokenTypes.LITERAL_CATCH;
          final DetailAstImpl astForTest1 = new DetailAstImpl();
          final DetailAstImpl astForTest2 = null;
          astForTest1.setType(type);
          final boolean result1 = TokenUtil.isOfType(type, TokenTypes.LITERAL_FOR,
                                  TokenTypes.LITERAL_IF, TokenTypes.LITERAL_ELSE);
          final boolean result2 = TokenUtil.isOfType(astForTest1, TokenTypes.LITERAL_FOR,
                                  TokenTypes.LITERAL_IF, TokenTypes.LITERAL_ELSE);
          final boolean result3 = TokenUtil.isOfType(astForTest2, TokenTypes.LITERAL_FOR,
                                  TokenTypes.LITERAL_IF, TokenTypes.LITERAL_ELSE);
  
          assertWithMessage("Token type should not match")
                  .that(result1)
                  .isFalse();
          assertWithMessage("Token type should not match")
                  .that(result2)
                  .isFalse();
          assertWithMessage("Token type should not match")
                  .that(result3)
                  .isFalse();
      }
  
      @Test
      public void testIsBooleanLiteralType() {
          assertWithMessage("Result is not expected")
                  .that(TokenUtil.isBooleanLiteralType(TokenTypes.LITERAL_TRUE))
                  .isTrue();
          assertWithMessage("Result is not expected")
                  .that(TokenUtil.isBooleanLiteralType(TokenTypes.LITERAL_FALSE))
                  .isTrue();
          assertWithMessage("Result is not expected")
                  .that(TokenUtil.isBooleanLiteralType(TokenTypes.LOR))
                  .isFalse();
      }
  
  }
  