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.KeyValueTimestamp;
  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.KStream;
  import org.apache.kafka.test.MockApiProcessorSupplier;
  import org.apache.kafka.test.StreamsTestUtils;
  
  import org.junit.jupiter.api.Test;
  
  import java.time.Duration;
  import java.time.Instant;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Properties;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  public class KStreamSelectKeyTest {
      private final String topicName = "topic_key_select";
      private final Properties props = StreamsTestUtils.getStreamsConfig(Serdes.String(), Serdes.Integer());
  
      @Test
      public void testSelectKey() {
          final StreamsBuilder builder = new StreamsBuilder();
  
          final Map<Number, String> keyMap = new HashMap<>();
          keyMap.put(1, "ONE");
          keyMap.put(2, "TWO");
          keyMap.put(3, "THREE");
  
          final KeyValueTimestamp[] expected = new KeyValueTimestamp[]{new KeyValueTimestamp<>("ONE", 1, 0),
              new KeyValueTimestamp<>("TWO", 2, 0),
              new KeyValueTimestamp<>("THREE", 3, 0)};
          final int[] expectedValues = new int[]{1, 2, 3};
  
          final KStream<String, Integer>  stream =
              builder.stream(topicName, Consumed.with(Serdes.String(), Serdes.Integer()));
          final MockApiProcessorSupplier<String, Integer, Void, Void> supplier = new MockApiProcessorSupplier<>();
          stream.selectKey((key, value) -> keyMap.get(value)).process(supplier);
  
          try (final TopologyTestDriver driver = new TopologyTestDriver(builder.build(), props)) {
              final TestInputTopic<String, Integer> inputTopic =
                      driver.createInputTopic(topicName, new StringSerializer(), new IntegerSerializer(), Instant.ofEpochMilli(0L), Duration.ZERO);
              for (final int expectedValue : expectedValues) {
                  inputTopic.pipeInput(expectedValue);
              }
          }
  
          assertEquals(3, supplier.theCapturedProcessor().processed().size());
          for (int i = 0; i < expected.length; i++) {
              assertEquals(expected[i], supplier.theCapturedProcessor().processed().get(i));
          }
      }
  
      @Test
      public void testTypeVariance() {
          new StreamsBuilder()
              .<Integer, String>stream("empty")
              .foreach((key, value) -> { });
      }
  }
  