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.sizes;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.checks.sizes.FileLengthCheck.MSG_KEY;
  
  import org.junit.jupiter.api.Test;
  
  import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
  import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
  import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  public class FileLengthCheckTest
      extends AbstractModuleTestSupport {
  
      @Override
      protected String getPackageLocation() {
          return "com/puppycrawl/tools/checkstyle/checks/sizes/filelength";
      }
  
      @Test
      public void testAlarm() throws Exception {
          final String[] expected = {
              "1: " + getCheckMessage(MSG_KEY, 228, 20),
          };
          verifyWithInlineConfigParser(
                  getPath("InputFileLength.java"), expected);
      }
  
      @Test
      public void testAlarmDefault() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputFileLengthDefault.java"), expected);
      }
  
      @Test
      public void testFileLengthEqualToMaxLength() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputFileLength2.java"), expected);
      }
  
      @Test
      public void testOk() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputFileLength3.java"), expected);
      }
  
      @Test
      public void testArgs() throws Exception {
          final DefaultConfiguration checkConfig =
              createModuleConfig(FileLengthCheck.class);
          try {
              checkConfig.addProperty("max", "abc");
              createChecker(checkConfig);
              assertWithMessage("Should indicate illegal args").fail();
          }
          catch (CheckstyleException ex) {
              assertWithMessage("Invalid exception message")
                  .that(ex.getMessage())
                  .isEqualTo("cannot initialize module com.puppycrawl.tools.checkstyle.checks."
                      + "sizes.FileLengthCheck - "
                      + "illegal value 'abc' for property 'max'");
          }
      }
  
      @Test
      public void testNoAlarmByExtension() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
  
          verifyWithInlineConfigParser(
                  getPath("InputFileLength4.java"), expected);
      }
  
      @Test
      public void testExtensions() {
          final FileLengthCheck check = new FileLengthCheck();
          check.setFileExtensions("java");
          assertWithMessage("extension should be the same")
              .that(check.getFileExtensions()[0])
              .isEqualTo(".java");
          check.setFileExtensions(".java");
          assertWithMessage("extension should be the same")
              .that(check.getFileExtensions()[0])
              .isEqualTo(".java");
          try {
              check.setFileExtensions((String[]) null);
              assertWithMessage("IllegalArgumentException is expected").fail();
          }
          catch (IllegalArgumentException ex) {
              assertWithMessage("Invalid exception message")
                  .that(ex.getMessage())
                  .isEqualTo("Extensions array can not be null");
          }
      }
  
  }
  