Testing stream topologies in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a test driver for a Kafka Streams topology.

Kafka

TopologyTestDriver driver = new TopologyTestDriver(topology, [1]);

Drag options to blanks, or click blank then click option'

Aprops

Bparameters

Csettings

Dconfig

Attempts:

3 left

💡 Hint

Common Mistakes

Passing an undefined variable instead of the configuration properties.

Using incorrect variable names like 'config' or 'settings'.

The TopologyTestDriver requires a Properties object named 'props' that contains the configuration for the test.

2fill in blank

medium

Complete the code to create an input topic for testing.

Kafka

TestInputTopic<String, String> inputTopic = driver.createInputTopic([1], stringSerializer, stringSerializer);

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AinputTopicName

BinputTopic

CtopicName

Dinput

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable that is not defined or does not hold the topic name.

Passing the wrong variable like 'inputTopic' which is the output variable.

The method createInputTopic requires the name of the topic as a string variable, commonly named 'topicName'.

3fill in blank

hard

Fix the error in the code to read output records from the output topic.

Kafka

TestOutputTopic<String, String> outputTopic = driver.createOutputTopic(outputTopicName, stringDeserializer, [1]);

Drag options to blanks, or click blank then click option'

AstringEncoder

BstringSerializer

CstringDecoder

DstringDeserializer

Attempts:

3 left

💡 Hint

Common Mistakes

Using a serializer instead of a deserializer for output topic.

Using incorrect classes like 'stringEncoder' or 'stringDecoder' which are not Kafka classes.

To read output records, you need to use a deserializer for the value, which is 'stringDeserializer'.

4fill in blank

hard

Fill both blanks to configure the properties for the test driver.

Kafka

Properties props = new Properties();
props.put(StreamsConfig.APPLICATION_ID_CONFIG, [1]);
props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, [2]);

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A"test-app"

B"localhost:9092"

C"kafka:9092"

D"app-test"

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect bootstrap server addresses.

Using application IDs that are not strings.

The application ID is usually a test name like 'test-app', and the bootstrap servers for local testing is 'localhost:9092'.

5fill in blank

hard

Fill all three blanks to send a record to the input topic and read from the output topic.

Kafka

inputTopic.pipeInput([1], [2]);
KeyValue<String, String> outputRecord = outputTopic.readKeyValue();
assertEquals([3], outputRecord.value);

Drag options to blanks, or click blank then click option'

A"key1"

B"inputValue"

C"expectedValue"

D"outputValue"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up input and expected output values.

Using keys or values not matching the test scenario.

You send the key 'key1' and value 'inputValue' to the input topic, then expect 'expectedValue' as the output value.