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;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  
  import java.util.Set;
  
  import org.junit.jupiter.api.Test;
  
  import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
  
  public class ThreadModeSettingsTest {
  
      @Test
      public void testProperties() {
          final ThreadModeSettings config = new ThreadModeSettings(1, 2);
          assertWithMessage("Invalid checker threads number")
                  .that(config.getCheckerThreadsNumber())
                  .isEqualTo(1);
          assertWithMessage("Invalid treewalker threads number")
                  .that(config.getTreeWalkerThreadsNumber())
                  .isEqualTo(2);
      }
  
      @Test
      public void testResolveCheckerInMultiThreadMode() {
          final ThreadModeSettings configuration = new ThreadModeSettings(2, 2);
  
          try {
              configuration.resolveName(ThreadModeSettings.CHECKER_MODULE_NAME);
              assertWithMessage("An exception is expected").fail();
          }
          catch (IllegalArgumentException ex) {
              assertWithMessage("Invalid exception message")
                      .that(ex.getMessage())
                      .isEqualTo("Multi thread mode for Checker module is not implemented");
          }
      }
  
      @Test
      public void testResolveCheckerInSingleThreadMode() {
          final ThreadModeSettings singleThreadMode = ThreadModeSettings.SINGLE_THREAD_MODE_INSTANCE;
  
          final String name = singleThreadMode.resolveName(ThreadModeSettings.CHECKER_MODULE_NAME);
          assertWithMessage("Invalid name resolved")
                  .that(name)
                  .isEqualTo(ThreadModeSettings.CHECKER_MODULE_NAME);
      }
  
      @Test
      public void testResolveTreeWalker() {
          final ThreadModeSettings configuration = new ThreadModeSettings(2, 2);
  
          try {
              configuration.resolveName(ThreadModeSettings.TREE_WALKER_MODULE_NAME);
              assertWithMessage("Exception is expected").fail();
          }
          catch (IllegalArgumentException ex) {
              assertWithMessage("Invalid exception message")
                      .that(ex.getMessage())
                      .isEqualTo("Multi thread mode for TreeWalker module is not implemented");
          }
      }
  
      @Test
      public void testResolveTreeWalkerInSingleThreadMode() {
          final ThreadModeSettings singleThreadMode = ThreadModeSettings.SINGLE_THREAD_MODE_INSTANCE;
          final String actual =
                  singleThreadMode.resolveName(ThreadModeSettings.TREE_WALKER_MODULE_NAME);
          assertWithMessage("Invalid name resolved: " + actual)
                  .that(actual)
                  .isEqualTo(ThreadModeSettings.TREE_WALKER_MODULE_NAME);
      }
  
      @Test
      public void testResolveAnyOtherModule() throws Exception {
          final Set<Class<?>> allModules = CheckUtil.getCheckstyleModules();
          final ThreadModeSettings multiThreadModeSettings = new ThreadModeSettings(2, 2);
          final ThreadModeSettings singleThreadModeSettings =
                  ThreadModeSettings.SINGLE_THREAD_MODE_INSTANCE;
  
          for (Class<?> module : allModules) {
              if (Checker.class.isAssignableFrom(module)
                      || TreeWalker.class.isAssignableFrom(module)) {
                  // they're handled in other tests
                  continue;
              }
  
              final String moduleName = module.getSimpleName();
              assertWithMessage("Invalid name resolved")
                      .that(singleThreadModeSettings.resolveName(moduleName))
                      .isEqualTo(moduleName);
              assertWithMessage("Invalid name resolved")
                      .that(multiThreadModeSettings.resolveName(moduleName))
                      .isEqualTo(moduleName);
          }
      }
  
  }
  