code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.rxjava3.testsupport;
  
  import org.junit.rules.TestRule;
  import org.junit.runner.Description;
  import org.junit.runners.model.Statement;
  
  import io.reactivex.rxjava3.exceptions.UndeliverableException;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  
  /**
   * A rule for suppressing UndeliverableException handling.
   *
   * <p>Test classes that use this rule can suppress UndeliverableException
   * handling by annotating the test method with SuppressUndeliverable.
   */
  public class SuppressUndeliverableRule implements TestRule {
  
      static final class SuppressUndeliverableRuleStatement extends Statement {
          private Statement base;
  
          SuppressUndeliverableRuleStatement(Statement base) {
              this.base = base;
          }
  
          @Override
          public void evaluate() throws Throwable {
              try {
                  RxJavaPlugins.setErrorHandler(throwable -> {
                      if (!(throwable instanceof UndeliverableException)) {
                          throwable.printStackTrace();
                          Thread currentThread = Thread.currentThread();
                          currentThread.getUncaughtExceptionHandler().uncaughtException(currentThread, throwable);
                      }
                  });
                  base.evaluate();
              } finally {
                  RxJavaPlugins.setErrorHandler(null);
              }
          }
      }
  
      @Override
      public Statement apply(Statement base, Description description) {
          if (description != null && description.getAnnotation(SuppressUndeliverable.class) != null) {
              return new SuppressUndeliverableRuleStatement(base);
          } else {
              return base;
          }
      }
  }
  