cadonna commented on a change in pull request #9615: URL: https://github.com/apache/kafka/pull/9615#discussion_r529858401
########## File path: streams/src/test/java/org/apache/kafka/streams/integration/AdjustStreamThreadCountTest.java ########## @@ -0,0 +1,104 @@ +/* + * 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.integration; + +import org.apache.kafka.common.serialization.Serdes; +import org.apache.kafka.streams.KafkaStreams; +import org.apache.kafka.streams.StreamsBuilder; +import org.apache.kafka.streams.StreamsConfig; +import org.apache.kafka.streams.integration.utils.EmbeddedKafkaCluster; +import org.apache.kafka.streams.integration.utils.IntegrationTestUtils; +import org.apache.kafka.streams.processor.ThreadMetadata; +import org.apache.kafka.test.IntegrationTest; +import org.apache.kafka.test.StreamsTestUtils; +import org.apache.kafka.test.TestUtils; +import org.hamcrest.CoreMatchers; +import org.junit.After; +import org.junit.Before; +import org.junit.ClassRule; +import org.junit.Rule; +import org.junit.Test; +import org.junit.experimental.categories.Category; +import org.junit.rules.TestName; + +import java.io.IOException; +import java.util.Optional; +import java.util.Properties; + +import static org.apache.kafka.common.utils.Utils.mkEntry; +import static org.apache.kafka.common.utils.Utils.mkMap; +import static org.apache.kafka.common.utils.Utils.mkObjectProperties; +import static org.apache.kafka.streams.integration.utils.IntegrationTestUtils.purgeLocalStreamsState; +import static org.apache.kafka.streams.integration.utils.IntegrationTestUtils.safeUniqueTestName; +import static org.hamcrest.CoreMatchers.equalTo; +import static org.hamcrest.MatcherAssert.assertThat; + +@Category(IntegrationTest.class) +public class AdjustStreamThreadCountTest { + + @ClassRule + public static final EmbeddedKafkaCluster CLUSTER = new EmbeddedKafkaCluster(1); + + @Rule + public TestName testName = new TestName(); + + private static String inputTopic; + private static StreamsBuilder builder; + private static Properties properties; + private static String appId = ""; + + @Before + public void setup() { + final String testId = safeUniqueTestName(getClass(), testName); + appId = "appId_" + testId; + inputTopic = "input" + testId; + IntegrationTestUtils.cleanStateBeforeTest(CLUSTER, inputTopic); + + builder = new StreamsBuilder(); + builder.stream(inputTopic); + + properties = mkObjectProperties( + mkMap( + mkEntry(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, CLUSTER.bootstrapServers()), + mkEntry(StreamsConfig.APPLICATION_ID_CONFIG, appId), + mkEntry(StreamsConfig.STATE_DIR_CONFIG, TestUtils.tempDirectory().getPath()), + mkEntry(StreamsConfig.NUM_STREAM_THREADS_CONFIG, 2), + mkEntry(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.StringSerde.class), + mkEntry(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.StringSerde.class) + ) + ); + } + + @After + public void teardown() throws IOException { + purgeLocalStreamsState(properties); + } + + @Test + public void shouldAddStreamThread() throws Exception { + try (final KafkaStreams kafkaStreams = new KafkaStreams(builder.build(), properties)) { + StreamsTestUtils.startKafkaStreamsAndWaitForRunningState(kafkaStreams); + final int oldThreadCount = kafkaStreams.localThreadsMetadata().size(); + + final Optional<String> name = kafkaStreams.addStreamThread(); + assertThat(name, CoreMatchers.not(Optional.empty())); + TestUtils.waitForCondition(() -> kafkaStreams.localThreadsMetadata().stream().sequential().map(ThreadMetadata::threadName).anyMatch(t -> t.equals(name.orElse(""))), + "Wait for the thread to be added"); + assertThat(kafkaStreams.localThreadsMetadata().size(), equalTo(oldThreadCount + 1)); Review comment: nit: If not all parameters fit on one line, we put each of them on a new line. Additionally we put also the closing parenthesis on a new line. nit: Lines should -- if possible -- not exceed 120 characters. nit: I like when tests are visually structured with one block for setup, the call under test, and one block for verifications. ```suggestion StreamsTestUtils.startKafkaStreamsAndWaitForRunningState(kafkaStreams); final int oldThreadCount = kafkaStreams.localThreadsMetadata().size(); final Optional<String> name = kafkaStreams.addStreamThread(); assertThat(name, CoreMatchers.not(Optional.empty())); TestUtils.waitForCondition( () -> kafkaStreams.localThreadsMetadata().stream().sequential() .map(ThreadMetadata::threadName).anyMatch(t -> t.equals(name.orElse(""))), "Wait for the thread to be added" ); assertThat(kafkaStreams.localThreadsMetadata().size(), equalTo(oldThreadCount + 1)); ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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