Technologies used in this article are: 1. For now, let's keep it simple and proceed. Kafka unit tests of the Producer code use MockProducer object. EXAMPLE 2: … Jesse+ by | Nov 16, 2016 | Blog, Business, Data Engineering, NP | 16 comments. Unit testing your Kafka code is incredibly important. I take for example the case of Spark Streaming using Kafka Receiver. Test using JUnit 5 in your Eclipse IDE. In this article, we will learn how to write JUnit test cases for Spring boot REST APIs. the 7 things you need to answer before making a career switch (page 77), the 15 Big Data technologies you should know (page 67), what you need to do to switch from your current title (page 46), © JESSE ANDERSON ALL RIGHTS RESERVED 2017-2020 jesse-anderson.com, The Ultimate Guide to Switching Careers to Big Data, https://kafka.apache.org/11/javadoc/org/apache/kafka/clients/consumer/MockConsumer.html#updateBeginningOffsets-java.util.Map-, https://kafka.apache.org/23/javadoc/org/apache/kafka/clients/consumer/MockConsumer.html#updateBeginningOffsets-java.util.Map-, Last week in Stream Processing & Analytics 11/21/2016 | Enjoy IT - SOA, Java, Event-Driven Computing and Integration. Kafka Load Testing. Most of the gained concision comes from treating input as first class objects that accept chained method invocations. I suggest you try again, actually learn Kafka, learn how to read comments in code, or maybe you need to learn how to code. This rule starts the Kafka and Zookeeper servers on … If you’re a Software Engineer or Data Analyst, I’ve written a book on switching careers to Big Data. Inside, I show you: How to switch careers: the 7 things you need to answer before making a career switch (page 77), What to learn: the 15 Big Data technologies you should know (page 67), Specific career advice: what you need to do to switch from your current title (page 46). There are often many different Consumers using the data. The most important finding in our study was that it is very important to maintain an affinity between producer threads and Kafka topics, such that any given topic will always be populated by the same producer thread. The EmbeddedKafkaRule constructor function takes the following values as parameters. Are you connecting to broker to get the real message? Here is a quickstart tutorial to implement a kafka publisher using Java and Maven. Here's an example of an integration test for the KafkaUnit class: Let's say you have some code that sends a message to Kafka, like this: A unit test would look something like this: It is in Maven Central, so if you want to use it just add the following dependency: info.batey.kafka kafka-unit In Kafka 0.9 two Mock classes was added: MockProducer and MockConsumer. Then we use this runner with the @RunWith annotation which will register our JUnit Listener to the test … Test classes may extend EmbeddedKafkaTest (JUnit 5) or EmbeddedKafkaJunit4Test (JUnit 4) to automatically start and stop an embedded Kafka broker. Kafka for JUnit provides JUnit 4.x rule implementations that enables developers to start and stop a complete Kafka cluster comprised of Kafka brokers and distributed Kafka Connect workers from within a JUnit test. In this example, we are going to test a simple module using stubs. beginningOffsets.put(topicPartition, 0L); Reply. Nowadays, event driven architecture is used in developing software applications in different areas, like microservices with patterns such as CQRS, Saga Pattern, etc. With the client.id defined as example above, each test executed is assigned a unique ID. Then we use this runner with the @RunWith annotation which will register our JUnit Listener to the test … We are done with the test case and ready to run. In the case of RAW, we just say it quietly: 2. JUnit 5 integration test with Spring Cloud Stream and embedded Kafka - DemoApplication.java. Last active Nov 24, 2020. a not-null value. What is JUnit? At last, we will see building the Kafka load testing scenario in Jmeter. Confluent Developer. "spring-kafka-test" includes an embedded Kafka server that can be created via a JUnit @ClassRule annotation. A quick note that this test only validates that the Consumer doesn’t throw an exception while processing this data. We need to bring up Docker with kafka prior to clicking any Junit tests. In this blog, we will explore a few examples to demonstrate how to use the testing utilities to validate topologies based on the Kafka Streams DSL API. First of all, you’ll need to be able to change your Consumer at runtime. The consume method is where your code starts to consume and process your messages. Furthermore it provides preconfigured consumer settings ( ConsumerSettings consumerDefaults ), The order of the fields doesn't really matter here. Create Project Directory It also provides a rich set of convenient accessors to interact with such an embedded Kafka cluster in a lean and non-obtrusive way. How to merge many streams into one stream. I strongly recommend reading through the Minimum Things We Need To Know For Kafka Testing post before proceeding with this tutorial. And, the order of the fields doesn't matter here. In this Apache Kafka tutorial, we will learn that by using Apache JMeter, how to perform Kafka Load Test at Apache Kafka. This helped us to build up and maintain our regression pack in an easy and clean manner. the size only, not the actual records. Once we’ve set the objects up, we can start testing. Test case. Kafka unit tests of the Consumer code use MockConsumer object. This blog post will show how you can setup your Kafka tests to use an embedded Kafka server. I get this exception when I code under test try to consume. libraryDependencies += "org.testcontainers" % "kafka" % "1.14.3" % Test Gradle dependencies { test group: 'org.testcontainers', name: 'kafka', version: '1.14.3' } The example below shows skeleton test classes for JUnit 4 and JUnit 5. I have more dependencies than the one in your sample but are not Kafka related. In this tutorial we will explore how to create test cases for Hive scripts and then show how to implement those test cases using HiveQLUnit. The spring-kafka-test jar contains some useful utilities to assist with testing your applications. 'consume':  "operation": "CONSUME". Postgres or Hadoop). We learned in the above section how to produce a record and assert the broker response/acknowledgment. What would you like to do? That's it. You could unit test this way, but I’d prefer mocking for unit tests. Here, we are going to use the Mockito framework along with the JUnit framework. As shown below is a basic junit test which uses camel-test-junit5.The createRouteBuilder method is used for build the routes to be tested. These tests are fast to run and easy to debug because their scope is small. Then the methods with @Test annotations are JUnit test methods which will be executed. Spring-kafka-test provides an embedded Kafka broker. Spring Boot Unit Test Simple Example. This verification is in the format of recordMetadata. The default value is 1. acks=0: "fire and forget", once the producer sends the record batch it is considered successful. JUnit’s capacity for running parameterized tests is an excellent way to generate quantitative results that can be used to optimize the throughput of your Kafka stream analytics. However, we may need to establish synchronous communication (request/reply) in some of the … What should we use instead of it? You need to refactor the actual consumption code so it doesn’t get stuck in an infinite loop. spring-kafka-test JAR that contains a number of useful utilities to assist you with your application unit testing Thank you Jesse your blogs have been extremely helpful getting me off the ground. Your email address will not be published. Test classes may extend EmbeddedKafkaTest (JUnit 5) or EmbeddedKafkaJunit4Test (JUnit 4) to automatically start and stop an embedded Kafka broker. Then the methods with @Test annotations are JUnit test methods which will be executed. Similarly, to write a "consumer" test, we need to know: The topic name 'demo-topic' is our "end point," a.k.a. You’ll want to unit test all of them. I hadn’t heard about any deprecation and my quick checks didn’t show any deprecations in the JavaDocs. But still, we have the flexibility to use the Kafka Client APIs and to add our own flavors to it. Unit testing your Kafka code is incredibly important. I just recomplied and reran this exact unit test. There may be times, for instance, that we validate only the number of records, i.e. It's a great time saver! Good luck! For example, visualizing the "recordMetaData" as JSON(or YAML) would look like: When we read or consume from a topic we can verify the record(s) fetched from the topics. EmbeddedKafkaRule. I’m really interested about Kafka and I’m trying to do a consumer and producer unit tests right now but I’m having some problems and doubts after read a lot of information about Kafka: 1)What is the difference between MockConsumer class/MockProducer class and EmbeddedKafka? Therefore, we need to cover all API contract validations in our end-to-end test scenarios, including Kafka. Also, the Consumer object often consumes in an infinite loop (while (true)). In this article, we will learn how to write JUnit test cases for Spring boot REST APIs. The operation, i.e. The default value is 100 milliseconds if you skip this flag. Test Exception in JUnit 3 In JUnit 3, or more exactly, in any versions of JUnit you can always use Java’s try-catch structure to test exception. Creating an Example Test Case . I have a quick question, I don’t seem to have consumer.updateBeginningOffsets in my version of Kafka 1.1.0, do you know which versions of Kafka this was added or removed and what the workaround could potentially be? This will give us good confidence in releasing our application to higher environments. You’ve found it. '@RunWith(ZeroCodeUnitRunner.class)' is a JUnit custom runner to run the test. It’s transporting your most important data. But still, we want to be able to test our code somehow without the need to start Zookeeper and Kafka server always. But do you think it's possible to test my Service with this example? Apache Kafka; Apache Spark & Scala; Search for: Python Tutorials; 4; Unit Testing With Python Unittest – Example & Working . In this Python Unittest tutorial, we will learn how to set up unit tests for our Python code. The Kafka broker will start before the first test and be stopped after all test classes are finished. In order to get hold of our ProducingChannel, we auto-wire the ApplicationContext and use the getBean() method. Do I need to use specific version of kafka for unit test? Join the DZone community and get the full member experience. Unit tests make sure that a unit of code is working as expected. We tell the Docker Compose framework (in a YAML file) to spin up certain things at certain ports, link certain services to other services, etc., and things are done for us by the framework. ... “By default, JUnit Jupiter tests are run sequentially in a single thread. "commitSync": true: Here, we are telling the test to do a `commitSync` after consuming the message, that means, it won't read the message again when you `poll` next time. JUnit 5 integration test with Spring Cloud Stream and embedded Kafka - DemoApplication. Hence it gives us flexibility for covering all kind of test scenarios. But it has a steep learning curve to deal with when it comes to Kafka brokers. JUnit is a simple, powerful, open source framework to write and run repeatable tests. With this dependency in place, an Embedded Kafka can be spun up in a test using the @ClassRule of JUnit: To run any test(s), we can directly navigate to their corresponding JUnit @Test, under 'src/test/java'. Our test code gets tightly coupled with the client API code. To write true integration tests you need a real-life Kafka working somewhere to test how your application cooperates with it. Kafka Load Testing. This code will need to be callable from the unit test. What is JUnit? Also, we will learn about the advantages of the declarative way of testing Kafka applications over the traditional/existing way of testing. JUnit test classes. There are two methods in TransformStreamTest annotated with @Test : testMovieConverter() and testTransformStream() . We will use JUnit 5 and Mockito to write the unit test cases. How to use. We can add this listener by creating a custom Runner. Kafka streams-test-utils example. This JUnit Listener can listen to events of JUnit lifecycle. For example, if you have three topics with five partitions each and you want to use concurrency=15, you see only five active consumers, each assigned one partition from each topic, with the other 10 consumers being idle. This JUnit Listener can listen to events of JUnit lifecycle. Though Kafka ships with some classes for testing, setting up a simple testing environment is quite easier with the kafka-unit library that offers JUnit test rule support or a fast programmatic setup within no time. For example, a use case could be that I want to see all messages will a specific key in one partition to maintain order. Once we are done, our full test will look like the code below: And that's it. It passed the tests when I first did the post too. Background: When using Apache Kafka, one concern raised is how to run unit tests for the consumers without the need to start a whole Kafka cluster and Zookeeper.. Embed. Have you been searching for the best data engineering training? consumer.updateBeginningOffsets(beginningOffsets); A JUnit 4 @Rule wrapper for the EmbeddedKafkaBroker is provided to create an embedded Kafka and an embedded Zookeeper server. Python Unittesting. In the following short example, I’d like to show how create a simple setup using Maven, Surefire and kafka-unit. A Quick and Practical Example of Kafka Testing, Testing a Kafka Consumer Consuming data from Kafka consists of two main steps. JUnit is a unit testing framework for the Java programming language and is by far the most popular framework for developing test cases in Java. Running JUnit tests with kafka-unit. Make sure you’re using the right object and arguments. Can you switch careers to Big Data in 4 months or less? And for the JSON record, we mention it in the same way: Note: The "value" section has a JSON record this time. The following code snippet shows a simple JUnit test that feeds 3 strings into a word count topology. Following code works for me: TopicPartition topicPartition = new TopicPartition(topic, 0); We can go further and ask our test to assert the "recordMetadata" field-by-field to verify it was written to the correct "partition" of the correct "topic" and much more, as shown below. spring-kafka: 2.4.5.RELEASE spring-kafka-test: 2.4.5.RELEASE junit-jupiter: 5.5.2 java: 1.8 no specific version mentioned for the dependency for spring-boot-starter and spring-boot-starter-test my application is currently testing locally on a window machine. For everything explained here, we can find running code examples in the "Conclusion" section of this post. Kafka has over 6,800 unit tests which validate individual components or small sets of components in isolation. I have a service who is communicating with a kafka server, and the problem is, when I import this service in my test and run the specific method who communicate with Kafka, it will send a message in my real kafka server. We then assert the broker acknowledgment. We will discuss this in the coming sections. "pollingTime": 500: Here, we are telling the test to poll for 500 milliseconds each time it polls. Add kafka-streams-test-utils to your project dependencies. Example: TestNG, JUnit, Mockito, etc. When we produce a record to a topic we can verify the acknowledgment from a Kafka broker. In the same end-to-end test, we can perform two steps like below for the same record(s): In the first place, there is nothing wrong in with the traditional style. There are many unit testing frameworks available in Java. Technologies used in this article are: Assert that the same record was present in the response, i.e. Contents. Note: this post was revised in January 20th, 2017 to reflect changes in Kafka. Yes, you can unit test any real consumer as shown here. Following are … Marketing Blog, Advantages of Declarative Style Testing (, Combining REST API Testing with Kafka Testing, Spinning Up Kafka in Docker - Single Node and Multi-Node, Produce to the topic "demo-topic" and validate the received. Next, you’ll want to refactor the code for creating your KafkaConsumer. Also, the Consumer object often consumes in an infinite loop (while (true)). The records, partitions, offsets, exception scenarios, etc. You’ll also need to refactor the code that consumes the data from the Consumer object. At last, we will see building the Kafka load testing scenario in Jmeter. We just need to point our JUnit @Test method to the JSON file. Instead of using the KafkaConsumer object directly, you’ll use the Consumer interface. The below code is also correct (field order swapped). There are many unit testing frameworks available in Java. We can use a JUnit @ClassRule annotation to create this Kafka broker. We are writing two test classes below for example only. The corresponding test case looks like below. The @Before will initialize the MockConsumer before each test. I mean, using the MockConsumer and MockProducer classes.. Embedded spins up a Kafka cluster. Sign up for my list so you can get my Professional Data Engineering course. All of the data added by the MockConsumer will be consumed by the Consumer. The Kafka broker will start before the first test and be stopped after all test classes are finished. This code will need to be callable from the unit test. The producer is working asynchronously and the test needs to poll for events for a reasonable amount of time to be certain that it has fetched all relevant events. I’m having same issue of not having MockConsumer updateBeginningOffsets and addRecord(..) ! That's it really. This is great because you will mostly write your code once and read it many times. Example Word Count Test without Fluent Kafka Streams Tests. In a previous post, I showed you how to unit test Producers. We eliminated the coding hassles of asserting each field key/value by traversing through their object path, parsing request-payloads, parsing response-payloads, etc. Next we define the Test class as follows-We load the camel-context.xml defined in the test/resources folder Define the mock endpoint and send the message. For example, if you have three topics with five partitions each and you want to use concurrency=15, you see only five active consumers, each assigned one partition from each topic, with the other 10 consumers being idle. Learn to merge many streams into one stream using Kafka Streams with full code examples. Testing a Kafka streams application requires a bit of test harness code, but happily the org.apache.kafka.streams.TopologyTestDriver class makes this much more pleasant that it would otherwise be. The methods are still there as of Kafka 2.3 https://kafka.apache.org/23/javadoc/org/apache/kafka/clients/consumer/MockConsumer.html#updateBeginningOffsets-java.util.Map-. I faced the same issue, the workaround for this is to assign new TopicPartition(topic, 0) to a variable and use that. libraryDependencies += "org.testcontainers" % "kafka" % "1.14.3" % Test Gradle dependencies { test group: 'org.testcontainers', name: 'kafka', version: '1.14.3' } The example below shows skeleton test classes for JUnit 4 and JUnit 5. At the same time, we used the JSON comparison feature of the framework to assert the outcome at once, therefore, making the tests a lot easier and cleaner. But we don't have to stop there. Kafka for JUnit provides JUnit 4.x rule implementations that enables developers to start and stop a complete Kafka cluster comprised of Kafka brokers and distributed Kafka Connect workers from within a JUnit test. Hi Jesse, great post I’ve attended your course on Kafka and learned quite a bit. Key-SerDe, Value-SerDe, Time-Outs while record Poolings, commitSyncs, recordTypes, etc., and many more things at the API level. An example of an enhanced mask component able to work with the image data. Here, we tell the test to use the Kafka-Topic which is our "end point" or "url", Next, we tell the test to use operation "produce". With this approach, we were able to cover a lot of test scenarios with full clarity and find more defects in the early stages of the development cycle, even without writing any test code. Note that we set … Contribute. In this article I suggest a new approach that can be helpful in case you want to write a unit-test for your code that implements Kafka Consumer. Are you tired of materials that don't go beyond the basics of data engineering. In this example we will show you how you can add a JUnit Listener to your test cases. The coverage of my tests is quite low due to differing construction requirements for the mock and concrete implementations but its a start. Regarding the Mock Producer and Consumer i understand they are now deprecated I don’t suppose you have any blogs on the new testing framework? These tests live in the src/test/java/ directory and rely on the JUnit 5 testing platform, which is automatically included when you create a project from the quick start. Unit Tests. We can go for an end-to-end testing approach which will validate both producing, consuming, and DLQ records as well as the application processing logic. This listener can be used for various purposes from improved logging to test specific logic. Free Confluent Cloud - Kafka tutorials with Confluent, the better for us ApplicationContext and the. Junit tests test scenarios but it has a steep learning curve to deal the. And contribute more Kafka tutorials with Confluent, the better for us test using JUnit 5 Mockito! The camel-context.xml defined in the JUnit test that feeds 3 strings into a Word count test without Fluent Kafka kafka junit test example... It would be if we have to do unit test all of them Listener... Your code once and read it many times tests you need a real-life Kafka somewhere. Is where your code the comparisons and assertions are instantly done the.! Please visit these RAW and JSON examples and explanations messages if any arrive on topic! Spring-Kafka-Test '' includes an embedded Kafka broker will start before the first test and be stopped after all test are. We define the test fast to run, great post I ’ ve always been.!... we need to use the suite runner or Package runner to run any test ( s from! Both ways…right on the topic uses a Kafka cluster applications built using Kafka Streams tests process as tests. Be set up such Kafka for unit tests test microservices involving both Kafka and REST of convenient to. You Jesse your blogs have been at the beginning: MockProducer and MockConsumer the Client API code at... Get stuck in an infinite loop ( while ( true ) ) issue of not having MockConsumer and! This exception when I code under test Try to consume events our end-to-end test.! To refactor the code for creating your KafkaConsumer mocking for unit testing Hive scripts I ’! Raw, we will see in next sections Kafka server find the docker-compose files and the step-by-step instructions.... Here, we learned in the above 'request ' means to do nothing consume... Default, JUnit Jupiter tests are fast to run the test … Stubbing example showed! Any deprecations in the declarative style, we just need to use to. Visit these RAW and JSON examples and explanations should be in separate method that won ’ t throw an while... 16 comments Hive scripts I get this exception when I first did the post Producers. Firstly, we are done, our full test will look like code... Are going to use specific version of the data done with the bespoke test framework code built inhouse skip... Case which contains kafka junit test example JSON step ( s ) we talked about that the... Really need to cover all API contract validations in our end-to-end test scenarios key-serde,,... Is 100 milliseconds if you skip this flag 2017 to reflect changes in Kafka Surefire and kafka-unit regression... Of materials that do n't match | 16 comments Hive scripts do think. Test suite updateBeginningOffsets and addRecord (.. ) consume method is where your code once and read it many.. Confluent Cloud - Kafka tutorials with Confluent, the MockConsumer before each test '... To reflect changes in Kafka object directly, including four broker nodes mock and concrete but. Advantages of the data from Kafka consists of two main steps and REST in a lean and non-obtrusive.... Assign topic partitions manually we finished comparing the expected vs. actual values created via a JUnit ClassRule! Compile, but I ’ m having same issue of not having MockConsumer updateBeginningOffsets and addRecord ( ) ( )! Mask component able to work with the Client API code following short example, we more. Your course on Kafka and Zookeeper servers on … unit tests org.springframework.kafka spring-kafka-test:1.1.2.BUILD-SNAPSHOT! In an infinite loop ( while ( true ) ) configs for a particular test or tests inside the locally! We are done with the brokers, we auto-wire the ApplicationContext and use the Mockito framework along with the test... Consumed by the Consumer we ’ re wanting to test how your application cooperates with it a Spring Boot APIs... Of RAW, we need a real-life Kafka working somewhere to test your! Gained concision comes from treating input as first class objects that accept chained invocations! Jesse your blogs have been at the API level the messages wheather consuming correct message or?. Code below: and that 's it as of Kafka for testing present in case! Following uses the JUnit test which uses camel-test-junit5.The createRouteBuilder method is used for various purposes from improved logging test! That do n't go beyond the basics of data Engineering course of RAW, we will see the... Run the entire test suite Javadoc of this class the end point for using the data to... Start off by instantiating the Consumer we ’ ve followed a couple your! Of these examples of the fields does n't matter here kafka junit test example a simple setup using Maven, Surefire and.... Confidence in releasing our application to higher environments object path, parsing request-payloads, parsing request-payloads parsing... Promote the artifacts to the JSON step ( s ) from the unit test all of them to create embedded! Software Engineer or data Analyst, I ’ m having same issue of not MockConsumer. The image data test using JUnit 5 and Mockito to write the unit case... True ) ) if they were produced to the higher environments $ 100 of Confluent... Testing done by the MockConsumer ’ s topic, partitions, and beginning offsets need to thoroughly get acquainted the. Cloud stream and embedded Kafka Jesse, great post I ’ m having same issue not! Debug because their scope is kafka junit test example can directly navigate to their corresponding JUnit @ test to... Has over 6,800 unit tests of the data to Big data debug your processor! Quick note that I am using a snapshot version of the testing done by the Consumer interface follows-We load camel-context.xml... Heard about any deprecation and my quick checks didn ’ t throw an exception while processing this data reduced! Consumer object often consumes in an infinite loop ( while ( true )! Show how create a simple setup using Maven, Surefire and kafka-unit createRouteBuilder method is used for various from. Producingchannel, we are going to test how your application cooperates with it test framework code built.... Scenarios, etc really need to Know for Kafka testing post before proceeding with this tutorial, we have records... Using the data added by the MockConsumer ’ s topic, we will learn how perform... Help test a simple, powerful, open source framework to write and run repeatable.. Code gets tightly coupled with the both ways…right | Nov 16, 2016 | Blog Business. Consuming message ( s ) from the unit test cases to merge many Streams into stream... Configure testing, see more at the Javadoc of this class is compared. Implement a Kafka cluster in a lean and non-obtrusive way. key/value by traversing through their path... Clarifying that MyTestConsumer is your code in January 20th, 2017 to reflect changes in Kafka two!

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