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.beam.runners.dataflow.worker;
  
  import static org.hamcrest.CoreMatchers.instanceOf;
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.hamcrest.Matchers.hasItem;
  
  import com.google.auto.service.AutoService;
  import java.io.Closeable;
  import java.io.IOException;
  import java.util.List;
  import org.apache.beam.runners.core.metrics.ExecutionStateTracker;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.JUnit4;
  
  /** Tests for ContextActivationObserverRegistry. */
  @RunWith(JUnit4.class)
  public class ContextActivationObserverRegistryTest {
  
    /** This type is used for testing the automatic registration mechanism. */
    private static class AutoRegistrationClass implements ContextActivationObserver {
      @Override
      public void close() throws IOException {}
  
      @Override
      public Closeable activate(ExecutionStateTracker e) {
        return this;
      }
    }
  
    /**
     * A {@link ContextActivationObserver.Registrar} to demonstrate default {@link
     * ContextActivationObserver} registration.
     */
    @AutoService(ContextActivationObserver.Registrar.class)
    public static class RegisteredTestContextActivationObserverRegistrar
        implements ContextActivationObserver.Registrar {
  
      @Override
      public boolean isEnabled() {
        return true;
      }
  
      @Override
      public ContextActivationObserver getContextActivationObserver() {
        return new AutoRegistrationClass();
      }
    }
  
    @Test
    public void testContextActivationObserverAll() throws Exception {
      ContextActivationObserverRegistry registry = ContextActivationObserverRegistry.createDefault();
      List<ContextActivationObserver> contextActivationObservers =
          registry.getContextActivationObservers();
  
      // Check that the registry contains AutoRegistrationClass.
      assertThat(contextActivationObservers, hasItem(instanceOf(AutoRegistrationClass.class)));
    }
  }
  