content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.bookkeeper.common.component;
  
  import static org.mockito.ArgumentMatchers.any;
  import static org.mockito.ArgumentMatchers.eq;
  import static org.mockito.Mockito.doAnswer;
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.times;
  import static org.mockito.Mockito.verify;
  import static org.mockito.Mockito.when;
  
  import java.lang.Thread.UncaughtExceptionHandler;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.atomic.AtomicReference;
  import org.apache.bookkeeper.common.component.ComponentStarter.ComponentShutdownHook;
  import org.junit.Test;
  
  /**
   * Test Case of {@link ComponentStarter}.
   */
  public class TestComponentStarter {
  
    @Test
    public void testStartComponent() {
      LifecycleComponent component = mock(LifecycleComponent.class);
      when(component.getName()).thenReturn("test-start-component");
      ComponentStarter.startComponent(component);
      verify(component).publishInfo(any(ComponentInfoPublisher.class));
      verify(component).start();
    }
  
    @Test
    public void testComponentShutdownHook() throws Exception {
      LifecycleComponent component = mock(LifecycleComponent.class);
      when(component.getName()).thenReturn("test-shutdown-hook");
      CompletableFuture<Void> future = new CompletableFuture<>();
      ComponentShutdownHook shutdownHook = new ComponentShutdownHook(component, future);
      shutdownHook.run();
      verify(component).close();
      future.get();
    }
  
    @Test
    public void testExceptionHandler() throws Exception {
      // prepare a mock lifecycle component
      LifecycleComponent component = mock(LifecycleComponent.class);
      when(component.getName()).thenReturn("test-exception-handler");
      AtomicReference<UncaughtExceptionHandler> exceptionHandlerRef = new AtomicReference<>();
      doAnswer(invocationOnMock -> {
          UncaughtExceptionHandler handler = invocationOnMock.getArgument(0);
          exceptionHandlerRef.set(handler);
          return null;
      }).when(component).setExceptionHandler(any(UncaughtExceptionHandler.class));
  
      // start the future
      CompletableFuture<Void> startFuture = ComponentStarter.startComponent(component);
      verify(component, times(1)).start();
      verify(component, times(1)).setExceptionHandler(eq(exceptionHandlerRef.get()));
  
      // if an exception is signaled through exception handler,
      // the startFuture will be completed and the component will be shutdown
      exceptionHandlerRef.get().uncaughtException(
          Thread.currentThread(), new Exception("test-exception-handler"));
  
      startFuture.get();
      verify(component, times(1)).close();
    }
  
  }
  