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Status
Current state: Under Discussion Discarded in favor of KIP-470: TopologyTestDriver test input and output usability improvements
Discussion thread: here
JIRA:
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package org.apache.kafka.streams.test; public class TestInputTopic<K, V> { //Timestamp handling //Record timestamp can be provided when piping input or use internally tracked time initialized with constructors: //startTimestampMs the initial timestamp for generated records, if not provided uses current system time as start timestamp. //autoAdvanceMs the time increment per generated record, if not provided auto-advance is disabled. //Constructors with serializers TestInputTopic(final TopologyTestDriver driver, final String topicName, final Serializer<K> keySerializer, final Serializer<V> valueSerializer); TestInputTopic(final TopologyTestDriver driver, final String topicName, final Serializer<K> keySerializer, final Serializer<V> valueSerializer, final long startTimestampMs); TestInputTopic(final TopologyTestDriver driver, final String topicName, final Serializer<K> keySerializer, final Serializer<V> valueSerializer, final long startTimestampMs, final long autoAdvanceMs); //Constructors with serdes TestInputTopic(final TopologyTestDriver driver, final String topicName, final Serde<K> keySerde, final Serde<V> valueSerde); TestInputTopic(final TopologyTestDriver driver, final String topicName, final Serde<K> keySerde, final Serde<V> valueSerde, final long startTimestampMs); TestInputTopic(final TopologyTestDriver driver, final String topicName, final Serde<K> keySerde, final Serde<V> valueSerde, final long startTimestampMs, final long autoAdvanceMs); //Advances the internally tracked time. void advanceTimeMs(final long advanceMs); //Methods to pipe single record void pipeInput(final V value); void pipeInput(final K key, final V value); void pipeInput(final V value, final long timestampMs); void pipeInput(final K key, final V value, final long timestampMs); void pipeInput(final K key, final V value, final Headers headers); void pipeInput(final K key, final V value, final Headers headers, final long timestampMs); //Methods to pipe list of records void pipeKeyValueList(final List<KeyValue<K, V>> keyValues); void pipeValueList(final List<V> values); void pipeKeyValueList(final List<KeyValue<K, V>> keyValues, final long startTimestamp, final long advanceMs); void pipeValueList(final List<V> values, final long startTimestamp, final long advanceMs); } |
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package org.apache.kafka.streams.test; public class TestOutputTopic<K, V> { //Constructor with serializers TestOutputTopic(final TopologyTestDriver driver, final String topic, final Serde<K> keySerde, final Serde<V> valueSerde); //Constructor with serdes TestOutputTopic(final TopologyTestDriver driver, final String topic, final Deserializer<K> keyDeserializer, final Deserializer<V> valueDeserializer); //Methods to readOutput ProducerRecord<K, V> readRecord(); KeyValue<K, V> readKeyValue(); V readValue(); //Output as collection Map<K, V> readKeyValuesToMap(); List<KeyValue<K, V>> readKeyValuesToList(); //If KPI-451 is included <K, V> Iterable<ProducerRecord<K, V>> iterableRecords(); <K, V> Iterable<KeyValue<K, V>> iterableKeyValues(); <V> Iterable<V> iterableValuesList<V> readValuesToList(); } |
Proposed Changes
This improvement adds TestInputTopic class which wraps TopologyTestDriver and ConsumerRecordFactory methods as one class to be used to write to Input Topics and TestOutputTopic class which collects TopologyTestDriver reading methods and provide typesafe read methods.
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public class SimpleTopicTest { private TopologyTestDriver testDriver; private TestInputTopic<String, String> inputTopic; private TestOutputTopic<String, String> outputTopic; @Before public void setup() { final StreamsBuilder buildertestDriver = new StreamsBuilder(); TestStream app = new TestStream(); //Create Actual Stream Processing pipeline app.createStream(builder); testDriver = new TopologyTestDriver(builder.build(),app.configTopologyTestDriver(TestStream.getTopology(), TestStream.getConfig()); inputTopic = new TestInputTopic<String, String>TestInputTopic<>(testDriver, TestStream.INPUT_TOPIC, new Serdes.StringSerde(), new Serdes.StringSerde()); outputTopic = new TestOutputTopic<String, String>TestOutputTopic<>(testDriver, TestStream.OUTPUT_TOPIC, new Serdes.StringSerde(), new Serdes.StringSerde()); } @After public void tearDown() { testDriver.close(); } @Test public void testOneWord() { //Feed word "Hello" to inputTopic and no kafka key, timestamp is irrelevant in this case inputTopic.pipeInput("Hello"); assertThat(outputTopic.readValue()).isEqualTo("Hello"); //No more output in topic assertThat(outputTopic.readRecord()).isNull(); } } |
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This is only adding new classes. The tests utilizing directly TopologyTestDriver can still be used. There are no compatibility issues.
Rejected Alternatives
- This version contains both original methods to fetch group of output as List or Map and It was considered to add methods to to return Iterable like in KIP-451: Make TopologyTestDriver output iterable is proposing similar with Iterable. The collection might be removed in favour of Iterable , but it seems to be redundant with these List based methods