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.imports;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheck.MSG_DUPLICATE;
  import static com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheck.MSG_LANG;
  import static com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheck.MSG_SAME;
  
  import java.io.File;
  import java.util.Arrays;
  import java.util.List;
  
  import org.junit.jupiter.api.Test;
  
  import com.google.common.collect.ImmutableMap;
  import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
  import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  public class RedundantImportCheckTest
      extends AbstractModuleTestSupport {
  
      @Override
      protected String getPackageLocation() {
          return "com/puppycrawl/tools/checkstyle/checks/imports/redundantimport";
      }
  
      @Test
      public void testGetRequiredTokens() {
          final RedundantImportCheck checkObj = new RedundantImportCheck();
          final int[] expected = {
              TokenTypes.IMPORT,
              TokenTypes.STATIC_IMPORT,
              TokenTypes.PACKAGE_DEF,
          };
          assertWithMessage("Default required tokens are invalid")
              .that(checkObj.getRequiredTokens())
              .isEqualTo(expected);
      }
  
      @Test
      public void testStateIsClearedOnBeginTree1()
              throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RedundantImportCheck.class);
          final String inputWithWarnings = getPath("InputRedundantImportCheckClearState.java");
          final String inputWithoutWarnings = getPath("InputRedundantImportWithoutWarnings.java");
          final List<String> expectedFirstInput = Arrays.asList(
              "10:1: " + getCheckMessage(MSG_DUPLICATE, 9, "java.util.Arrays.asList"),
              "13:1: " + getCheckMessage(MSG_DUPLICATE, 12, "java.util.List")
          );
          final List<String> expectedSecondInput = Arrays.asList(CommonUtil.EMPTY_STRING_ARRAY);
          final File[] inputs = {new File(inputWithWarnings), new File(inputWithoutWarnings)};
  
          verify(createChecker(checkConfig), inputs, ImmutableMap.of(
              inputWithWarnings, expectedFirstInput,
              inputWithoutWarnings, expectedSecondInput));
      }
  
      @Test
      public void testWithChecker()
              throws Exception {
          final String[] expected = {
              "9:1: " + getCheckMessage(MSG_SAME,
                  "com.puppycrawl.tools.checkstyle.checks.imports.redundantimport.*"),
              "10:1: " + getCheckMessage(MSG_SAME,
                  "com.puppycrawl.tools.checkstyle.checks.imports.redundantimport."
                          + "InputRedundantImportBug"),
              "12:1: " + getCheckMessage(MSG_LANG, "java.lang.*"),
              "13:1: " + getCheckMessage(MSG_LANG, "java.lang.String"),
              "16:1: " + getCheckMessage(MSG_DUPLICATE, 15, "java.util.List"),
              "28:1: " + getCheckMessage(MSG_DUPLICATE, 27, "javax.swing.WindowConstants.*"),
          };
          verifyWithInlineConfigParser(
                  getPath("InputRedundantImportWithChecker.java"), expected);
      }
  
      @Test
      public void testUnnamedPackage()
              throws Exception {
          final String[] expected = {
              "10:1: " + getCheckMessage(MSG_DUPLICATE, 9, "java.util.List"),
              "12:1: " + getCheckMessage(MSG_LANG, "java.lang.String"),
          };
          verifyWithInlineConfigParser(
                  getNonCompilablePath("InputRedundantImport_UnnamedPackage.java"),
              expected);
      }
  
      @Test
      public void testGetAcceptableTokens() {
          final RedundantImportCheck testCheckObject =
                  new RedundantImportCheck();
          final int[] actual = testCheckObject.getAcceptableTokens();
          final int[] expected = {
              TokenTypes.IMPORT,
              TokenTypes.STATIC_IMPORT,
              TokenTypes.PACKAGE_DEF,
          };
  
          assertWithMessage("Default acceptable tokens are invalid")
              .that(actual)
              .isEqualTo(expected);
      }
  
      @Test
      public void testBeginTreePackage() throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RedundantImportCheck.class);
          final String file1 = getPath("InputRedundantImportCheckClearState.java");
          final String file2 = getPath("InputRedundantImportWithoutPackage.java");
          final List<String> expectedFirstInput = Arrays.asList(
              "10:1: " + getCheckMessage(MSG_DUPLICATE, 9, "java.util.Arrays.asList"),
              "13:1: " + getCheckMessage(MSG_DUPLICATE, 12, "java.util.List")
          );
          final List<String> expectedSecondInput = Arrays.asList(
              "9:1: " + getCheckMessage(MSG_LANG, "java.lang.*"),
              "10:1: " + getCheckMessage(MSG_LANG, "java.lang.String")
          );
          final File[] inputs = {new File(file1), new File(file2)};
          verify(createChecker(checkConfig), inputs, ImmutableMap.of(
              file1, expectedFirstInput,
              file2, expectedSecondInput));
      }
  }
  