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.ParameterAssignmentCheck.MSG_KEY;
  
  import java.io.File;
  import java.util.Collection;
  import java.util.Optional;
  import java.util.Set;
  
  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 ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
  
      @Override
      protected String getPackageLocation() {
          return "com/puppycrawl/tools/checkstyle/checks/coding/parameterassignment";
      }
  
      @Test
      public void testDefault()
              throws Exception {
          final String[] expected = {
              "17:15: " + getCheckMessage(MSG_KEY, "field"),
              "18:15: " + getCheckMessage(MSG_KEY, "field"),
              "20:14: " + getCheckMessage(MSG_KEY, "field"),
              "28:30: " + getCheckMessage(MSG_KEY, "field1"),
              "45:31: " + getCheckMessage(MSG_KEY, "q"),
              "46:39: " + getCheckMessage(MSG_KEY, "q"),
              "47:34: " + getCheckMessage(MSG_KEY, "w"),
              "49:41: " + getCheckMessage(MSG_KEY, "w"),
              "50:49: " + getCheckMessage(MSG_KEY, "a"),
              "52:11: " + getCheckMessage(MSG_KEY, "c"),
              "53:11: " + getCheckMessage(MSG_KEY, "d"),
              "63:15: " + getCheckMessage(MSG_KEY, "d"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputParameterAssignmentWithUnchecked.java"),
                 expected);
      }
  
      @Test
      public void testReceiverParameter() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputParameterAssignmentReceiver.java"), expected);
      }
  
      @Test
      public void testEnhancedSwitch() throws Exception {
          final String[] expected = {
              "14:28: " + getCheckMessage(MSG_KEY, "a"),
              "21:16: " + getCheckMessage(MSG_KEY, "result"),
          };
          verifyWithInlineConfigParser(
                  getNonCompilablePath("InputParameterAssignmentWithEnhancedSwitch.java"),
                  expected);
      }
  
      @Test
      public void testTokensNotNull() {
          final ParameterAssignmentCheck check = new ParameterAssignmentCheck();
          assertWithMessage("Acceptable tokens should not be null")
              .that(check.getAcceptableTokens())
              .isNotNull();
          assertWithMessage("Default tokens should not be null")
              .that(check.getDefaultTokens())
              .isNotNull();
          assertWithMessage("Required tokens should not be null")
              .that(check.getRequiredTokens())
              .isNotNull();
      }
  
      /**
       * We cannot reproduce situation when visitToken is called and leaveToken is not.
       * So, we have to use reflection to be sure that even in such situation
       * state of the field will be cleared.
       *
       * @throws Exception when code tested throws exception
       */
      @Test
      @SuppressWarnings("unchecked")
      public void testClearState() throws Exception {
          final ParameterAssignmentCheck check = new ParameterAssignmentCheck();
          final Optional<DetailAST> methodDef = TestUtil.findTokenInAstByPredicate(
              JavaParser.parseFile(new File(getPath("InputParameterAssignmentReceiver.java")),
                  JavaParser.Options.WITHOUT_COMMENTS),
              ast -> ast.getType() == TokenTypes.METHOD_DEF);
  
          assertWithMessage("Ast should contain METHOD_DEF")
                  .that(methodDef.isPresent())
                  .isTrue();
          assertWithMessage("State is not cleared on beginTree")
              .that(TestUtil.isStatefulFieldClearedDuringBeginTree(check, methodDef.get(),
                  "parameterNamesStack",
                  parameterNamesStack -> ((Collection<Set<String>>) parameterNamesStack).isEmpty()))
              .isTrue();
      }
  
  }
  