streams/src/test/java/org/apache/kafka/streams/kstream/internals/KTableMapKeysTest.java

/**
 * 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.Serde;
import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.streams.kstream.KStream;
import org.apache.kafka.streams.kstream.KStreamBuilder;
import org.apache.kafka.streams.kstream.KTable;
import org.apache.kafka.streams.kstream.KeyValueMapper;
import org.apache.kafka.test.KStreamTestDriver;
import org.apache.kafka.test.MockProcessorSupplier;
import org.junit.After;
import org.junit.Test;

import java.util.HashMap;
import java.util.Map;

import static org.junit.Assert.assertEquals;

public class KTableMapKeysTest {

    final private Serde<String> stringSerde = new Serdes.StringSerde();
    final private Serde<Integer>  integerSerde = new Serdes.IntegerSerde();

    private KStreamTestDriver driver = null;

    @After
    public void cleanup() {
        if (driver != null) {
            driver.close();
        }
        driver = null;
    }

    @Test
    public void testMapKeysConvertingToStream() {
        final KStreamBuilder builder = new KStreamBuilder();

        String topic1 = "topic_map_keys";

        KTable<Integer, String> table1 = builder.table(integerSerde, stringSerde, topic1);

        final Map<Integer, String> keyMap = new HashMap<>();
        keyMap.put(1, "ONE");
        keyMap.put(2, "TWO");
        keyMap.put(3, "THREE");

        KeyValueMapper<Integer, String, String> keyMapper = new KeyValueMapper<Integer, String, String>() {
            @Override
            public  String apply(Integer key, String value) {
                return keyMap.get(key);
            }
        };

        KStream<String, String> convertedStream = table1.toStream(keyMapper);

        final String[] expected = new String[]{"ONE:V_ONE", "TWO:V_TWO", "THREE:V_THREE"};
        final int[] originalKeys = new int[]{1, 2, 3};
        final String[] values = new String[]{"V_ONE", "V_TWO", "V_THREE"};



        MockProcessorSupplier<String, String> processor = new MockProcessorSupplier<>();

        convertedStream.process(processor);

        driver = new KStreamTestDriver(builder);

        for (int i = 0;  i < originalKeys.length; i++) {
            driver.process(topic1, originalKeys[i], values[i]);
        }

        assertEquals(3, processor.processed.size());

        for (int i = 0; i < expected.length; i++) {
            assertEquals(expected[i], processor.processed.get(i));
        }
    }



}