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.checks.coding;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.checks.coding.UnusedLocalVariableCheck.MSG_UNUSED_LOCAL_VARIABLE;
  
  import java.io.File;
  import java.util.Collection;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.function.Predicate;
  
  import org.junit.jupiter.api.Test;
  
  import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
  import com.puppycrawl.tools.checkstyle.JavaParser;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
  
      @Override
      protected String getPackageLocation() {
          return "com/puppycrawl/tools/checkstyle/checks/coding/unusedlocalvariable";
      }
  
      @Test
      public void testGetRequiredTokens() {
          final UnusedLocalVariableCheck checkObj =
                  new UnusedLocalVariableCheck();
          final int[] actual = checkObj.getRequiredTokens();
          final int[] expected = {
              TokenTypes.DOT,
              TokenTypes.VARIABLE_DEF,
              TokenTypes.IDENT,
              TokenTypes.SLIST,
              TokenTypes.LITERAL_FOR,
              TokenTypes.OBJBLOCK,
              TokenTypes.CLASS_DEF,
              TokenTypes.INTERFACE_DEF,
              TokenTypes.ANNOTATION_DEF,
              TokenTypes.PACKAGE_DEF,
              TokenTypes.LITERAL_NEW,
              TokenTypes.METHOD_DEF,
              TokenTypes.CTOR_DEF,
              TokenTypes.STATIC_INIT,
              TokenTypes.INSTANCE_INIT,
              TokenTypes.COMPILATION_UNIT,
              TokenTypes.LAMBDA,
              TokenTypes.ENUM_DEF,
              TokenTypes.RECORD_DEF,
              TokenTypes.COMPACT_CTOR_DEF,
          };
          assertWithMessage("Required tokens are invalid")
                  .that(actual)
                  .isEqualTo(expected);
      }
  
      @Test
      public void testGetAcceptableTokens() {
          final UnusedLocalVariableCheck typeParameterNameCheckObj =
                  new UnusedLocalVariableCheck();
          final int[] actual = typeParameterNameCheckObj.getAcceptableTokens();
          final int[] expected = {
              TokenTypes.DOT,
              TokenTypes.VARIABLE_DEF,
              TokenTypes.IDENT,
              TokenTypes.SLIST,
              TokenTypes.LITERAL_FOR,
              TokenTypes.OBJBLOCK,
              TokenTypes.CLASS_DEF,
              TokenTypes.INTERFACE_DEF,
              TokenTypes.ANNOTATION_DEF,
              TokenTypes.PACKAGE_DEF,
              TokenTypes.LITERAL_NEW,
              TokenTypes.METHOD_DEF,
              TokenTypes.CTOR_DEF,
              TokenTypes.STATIC_INIT,
              TokenTypes.INSTANCE_INIT,
              TokenTypes.COMPILATION_UNIT,
              TokenTypes.LAMBDA,
              TokenTypes.ENUM_DEF,
              TokenTypes.RECORD_DEF,
              TokenTypes.COMPACT_CTOR_DEF,
          };
          assertWithMessage("Acceptable tokens are invalid")
                  .that(actual)
                  .isEqualTo(expected);
      }
  
      @Test
      public void testUnusedLocalVariable() throws Exception {
          final String[] expected = {
              "27:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "sameName"),
              "28:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "31:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "testInLambdas"),
              "33:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "coding"),
              "34:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE,
                      "InputUnusedLocalVariable"),
              "50:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "54:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "c"),
              "65:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "67:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "c"),
              "71:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "p"),
              "81:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "f"),
              "84:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "foo"),
              "91:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariable.java"), expected);
      }
  
      @Test
      public void testUnusedLocalVar2() throws Exception {
          final String[] expected = {
              "17:14: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "i"),
              "19:14: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "j"),
              "30:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "31:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "39:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "40:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "Test"),
              "41:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
              "61:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "76:17: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariable2.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarInAnonInnerClasses() throws Exception {
          final String[] expected = {
              "14:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "15:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "17:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
              "22:17: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
              "32:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj2"),
              "46:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "m"),
              "47:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "l"),
              "59:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "h"),
              "62:17: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "v"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableAnonInnerClasses.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarGenericAnonInnerClasses() throws Exception {
          final String[] expected = {
              "13:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "l"),
              "14:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
              "33:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "l"),
              "34:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj2"),
              "47:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "s"),
              "67:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "variable"),
              "69:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "anotherVar"),
              "78:47: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj2"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableGenericAnonInnerClasses.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarDepthOfClasses() throws Exception {
          final String[] expected = {
              "28:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "r"),
              "49:21: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "64:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "94:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "variable"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableDepthOfClasses.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarNestedClasses() throws Exception {
          final String[] expected = {
              "21:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "V"),
              "23:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "S"),
              "24:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "Q"),
              "36:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "variable"),
              "44:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "anotherVariable"),
              "67:21: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "s"),
              "68:21: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "n"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableNestedClasses.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarNestedClasses2() throws Exception {
          final String[] expected = {
              "29:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "q"),
              "30:51: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
              "46:21: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "57:21: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "108:33: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "s"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableNestedClasses2.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarNestedClasses3() throws Exception {
          final String[] expected = {
              "36:17: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "p2"),
              "54:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "o"),
              "93:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
              "95:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
          };
  
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableNestedClasses3.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarTestWarningSeverity() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
  
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableTestWarningSeverity.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarEnum() throws Exception {
          final String[] expected = {
              "22:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "50:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "77:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "80:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "j"),
              "92:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "d"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableEnum.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarRecords() throws Exception {
          final String[] expected = {
              "16:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var1"),
              "25:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var1"),
              "26:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
              "36:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var2"),
          };
          verifyWithInlineConfigParser(
                  getNonCompilablePath("InputUnusedLocalVariableRecords.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVarWithoutPackageStatement() throws Exception {
          final String[] expected = {
              "12:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
              "24:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var2"),
              "45:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var3"),
          };
          verifyWithInlineConfigParser(
                  getNonCompilablePath("InputUnusedLocalVariableWithoutPackageStatement.java"),
                  expected);
      }
  
      @Test
      public void testUnusedLocalVariableTernaryAndExpressions() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputUnusedLocalVariableTernaryAndExpressions.java"),
                  expected);
      }
  
      @Test
      public void testClearStateVariables() throws Exception {
          final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
          final Optional<DetailAST> methodDef = TestUtil.findTokenInAstByPredicate(
                  JavaParser.parseFile(
                          new File(getPath("InputUnusedLocalVariable.java")),
                          JavaParser.Options.WITHOUT_COMMENTS),
                  ast -> ast.getType() == TokenTypes.METHOD_DEF);
          assertWithMessage("Ast should contain METHOD_DEF")
                  .that(methodDef.isPresent())
                  .isTrue();
          final DetailAST variableDef = methodDef.get().getLastChild()
                  .findFirstToken(TokenTypes.VARIABLE_DEF);
          assertWithMessage("State is not cleared on beginTree")
                  .that(TestUtil.isStatefulFieldClearedDuringBeginTree(check, variableDef,
                          "variables",
                          variables -> {
                              return ((Collection<?>) variables).isEmpty();
                          }))
                  .isTrue();
      }
  
      @Test
      public void testClearStateClasses() throws Exception {
          final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
          final Optional<DetailAST> classDef = TestUtil.findTokenInAstByPredicate(
                  JavaParser.parseFile(
                          new File(getPath("InputUnusedLocalVariable.java")),
                          JavaParser.Options.WITHOUT_COMMENTS),
                  ast -> ast.getType() == TokenTypes.CLASS_DEF);
          assertWithMessage("Ast should contain CLASS_DEF")
                  .that(classDef.isPresent())
                  .isTrue();
          final DetailAST classDefToken = classDef.get();
          assertWithMessage("State is not cleared on beginTree")
                  .that(TestUtil.isStatefulFieldClearedDuringBeginTree(check, classDefToken,
                          "typeDeclarations",
                          typeDeclarations -> {
                              return ((Collection<?>) typeDeclarations).isEmpty();
                          }))
                  .isTrue();
          assertWithMessage("State is not cleared on beginTree")
                  .that(TestUtil.isStatefulFieldClearedDuringBeginTree(check, classDefToken,
                          "typeDeclAstToTypeDeclDesc",
                          typeDeclAstToTypeDeclDesc -> {
                              return ((Map<?, ?>) typeDeclAstToTypeDeclDesc).isEmpty();
                          }))
                  .isTrue();
          assertWithMessage("State is not cleared on beginTree")
                  .that(TestUtil.isStatefulFieldClearedDuringBeginTree(check, classDefToken,
                          "depth",
                          depth -> {
                              return (int) depth == 0;
                          }))
                  .isTrue();
      }
  
      @Test
      public void testClearStateAnonInnerClass() throws Exception {
          final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
          final DetailAST root = JavaParser.parseFile(
                  new File(getPath("InputUnusedLocalVariableAnonInnerClasses.java")),
                  JavaParser.Options.WITHOUT_COMMENTS);
          // Not using TestUtil.isStatefulFieldClearedDuringBeginTree(..) because other
          // nodes need to be processed first as those collections, maps are dependent on them.
          final DetailAST classDefAst = root.findFirstToken(TokenTypes.CLASS_DEF);
          final Optional<DetailAST> literalNew = TestUtil.findTokenInAstByPredicate(root,
                  ast -> ast.getType() == TokenTypes.LITERAL_NEW);
          assertWithMessage("Ast should contain LITERAL_NEW")
                  .that(literalNew.isPresent())
                  .isTrue();
          check.beginTree(root);
          check.visitToken(classDefAst);
          check.visitToken(literalNew.get());
          check.beginTree(null);
          final Predicate<Object> isClear = anonInnerAstToTypeDesc -> {
              return ((Map<?, ?>) anonInnerAstToTypeDesc).isEmpty();
          };
          assertWithMessage("State is not cleared on beginTree")
                  .that(isClear.test(TestUtil.getInternalState(
                          check, "anonInnerAstToTypeDeclDesc")))
                  .isTrue();
          final Predicate<Object> isQueueClear = anonInnerClassHolders -> {
              return ((Collection<?>) anonInnerClassHolders).isEmpty();
          };
          assertWithMessage("State is not cleared on beginTree")
                  .that(isQueueClear.test(TestUtil.getInternalState(
                          check, "anonInnerClassHolders")))
                  .isTrue();
      }
  
      @Test
      public void testClearStatePackageDef() throws Exception {
          final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
          final Optional<DetailAST> packageDef = TestUtil.findTokenInAstByPredicate(
                  JavaParser.parseFile(
                          new File(getPath("InputUnusedLocalVariable.java")),
                          JavaParser.Options.WITHOUT_COMMENTS),
                  ast -> ast.getType() == TokenTypes.PACKAGE_DEF);
          assertWithMessage("Ast should contain PACKAGE_DEF")
                  .that(packageDef.isPresent())
                  .isTrue();
          final DetailAST packageDefToken = packageDef.get();
          assertWithMessage("State is not cleared on beginTree")
                  .that(TestUtil.isStatefulFieldClearedDuringBeginTree(check, packageDefToken,
                          "packageName",
                          Objects::isNull))
                  .isTrue();
      }
  }
  