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.kafka.streams.kstream.internals;
  
  import org.apache.kafka.common.serialization.IntegerSerializer;
  import org.apache.kafka.common.serialization.Serdes;
  import org.apache.kafka.common.serialization.StringSerializer;
  import org.apache.kafka.streams.KeyValue;
  import org.apache.kafka.streams.StreamsBuilder;
  import org.apache.kafka.streams.TestInputTopic;
  import org.apache.kafka.streams.TopologyTestDriver;
  import org.apache.kafka.streams.kstream.Consumed;
  import org.apache.kafka.streams.kstream.ForeachAction;
  import org.apache.kafka.streams.kstream.KStream;
  import org.apache.kafka.test.StreamsTestUtils;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Locale;
  import java.util.Properties;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  public class KStreamForeachTest {
  
      private final String topicName = "topic";
      private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.Integer(), Serdes.String());
  
      @Test
      public void testForeach() {
          // Given
          final List<KeyValue<Integer, String>> inputRecords = Arrays.asList(
              new KeyValue<>(0, "zero"),
              new KeyValue<>(1, "one"),
              new KeyValue<>(2, "two"),
              new KeyValue<>(3, "three")
          );
  
          final List<KeyValue<Integer, String>> expectedRecords = Arrays.asList(
              new KeyValue<>(0, "ZERO"),
              new KeyValue<>(2, "ONE"),
              new KeyValue<>(4, "TWO"),
              new KeyValue<>(6, "THREE")
          );
  
          final List<KeyValue<Integer, String>> actualRecords = new ArrayList<>();
          final ForeachAction<Integer, String> action =
              (key, value) -> actualRecords.add(new KeyValue<>(key * 2, value.toUpperCase(Locale.ROOT)));
  
          // When
          final StreamsBuilder builder = new StreamsBuilder();
          final KStream<Integer, String> stream = builder.stream(topicName, Consumed.with(Serdes.Integer(), Serdes.String()));
          stream.foreach(action);
  
          // Then
          try (final TopologyTestDriver driver = new TopologyTestDriver(builder.build(), props)) {
              final TestInputTopic<Integer, String> inputTopic = driver.createInputTopic(topicName, new IntegerSerializer(), new StringSerializer());
              for (final KeyValue<Integer, String> record : inputRecords) {
                  inputTopic.pipeInput(record.key, record.value);
              }
          }
  
          assertEquals(expectedRecords.size(), actualRecords.size());
          for (int i = 0; i < expectedRecords.size(); i++) {
              final KeyValue<Integer, String> expectedRecord = expectedRecords.get(i);
              final KeyValue<Integer, String> actualRecord = actualRecords.get(i);
              assertEquals(expectedRecord, actualRecord);
          }
      }
  
      @Test
      public void testTypeVariance() {
          final ForeachAction<Number, Object> consume = (key, value) -> { };
  
          new StreamsBuilder()
              .<Integer, String>stream("emptyTopic")
              .foreach(consume);
      }
  }
  