REST call - Query (GET) the "Address" REST API by using "/api/v1/addresses/id-lon-123" and assert the response. "spring-kafka-test" includes an embedded Kafka server that can be created via a JUnit @ClassRule annotation. The Kafka broker will start before the first test and be stopped after all test classes are finished. By now it comes with JUnit 5 as well, so you are ready to go. Using this approach, we have tested and validated clustered Kafka Data Pipelines to Hadoop as well as Http REST and SOAP APIs deployed in Kubernetes orchestrated pods. keep on changing, making it difficult to think in terms of what to test, when to test, and how to test. We use publish-subscribe messaging systems such as Apache Kafka, for asynchronous communication between systems. Also we verify the message count for the test … The below code is also correct (field order swapped). This is because the default Kafka PartitionAssignor is the RangeAssignor (see its Javadoc). There are many ways you can set up such Kafka for testing. What is JUnit? The complete source code of these examples of the repo GitHub (Try at Home) are given below. There are solutions like embedded Kafka (for example in spring-kafka-test) that runs broker within the same process as your tests. We will discuss this in the coming sections. We can find the docker-compose files and the step-by-step instructions below. The "assertion" block is instantly compared against the actual "status" and "recordMetadata" received from the Kafka Broker. Stubbing example. There are often many different Consumers using the data. The default value is 1. That's it really. We start off by instantiating the Consumer we’re wanting to test. We found this approach very, very straight forward and reduced complexity to maintain and promote the artifacts to the higher environments. In order to get hold of our ProducingChannel, we auto-wire the ApplicationContext and use the getBean() method. Examples of Mockito and JUnit in Eclipse IDE. Kafka unit tests of the Consumer code use MockConsumer object. 2)I can to do unit test with the both ways…right? It’s transporting your most important data. Running JUnit tests with kafka-unit. In this post we will write test cases for a Spring Boot Application. For the first time, thank you about your info. Here, we are going to use the Mockito framework along with the JUnit framework. Most of the gained concision comes from treating input as first class objects that accept chained method invocations. We then assert the broker acknowledgment. In this part, you will test the stream processor using kafka-streams-test-utils and JUnit 5. Do you even run the code you write here? Learn to merge many streams into one stream using Kafka Streams with full code examples. First of all, you’ll need to be able to change your Consumer at runtime. If you’re a Software Engineer or Data Analyst, I’ve written a book on switching careers to Big Data. Next, we need to send the records to the request payload: Then, we tell the test that we are expecting the response "status" to be returned as "Ok" and some record metadata from the broker, i.e. Then the methods with @Test annotations are JUnit test methods which will be executed. Also, the Consumer object often consumes in an infinite loop (while (true)). In this tutorial, we will quickly explore some basic to high-level approaches for testing microservice applications built using Kafka. phillipuniverse / DemoApplication.java. Have you been searching for the best data engineering training? A quick note that this test only validates that the Consumer doesn’t throw an exception while processing this data. spring-kafka-test JAR that contains a number of useful utilities to assist you with your application unit testing This JUnit Listener can listen to events of JUnit lifecycle. Also, we learned how easily we can test microservices involving both Kafka and REST. 1. This is especially true for your Consumers. Unit Testing is a one of the testing done by the developers to make sure individual unit or component functionalities are working fine. ... How would you test if partitioning is taking place correctly in the JUnit test? "maxNoOfRetryPollsOrTimeouts": 3: Here, we are telling the test to show the poll a maximum of three times, then stop polling. '@RunWith(ZeroCodeUnitRunner.class)' is a JUnit custom runner to run the test. JUnit test classes. For testing I will show you how to use Embedded Kafka. Automating that process with parametrized JUnit tests is an excellent way to optimize Kafka without guess work and without wasting time. With the client.id defined as example above, each test executed is assigned a unique ID. Nowadays, event driven architecture is used in developing software applications in different areas, like microservices with patterns such as CQRS, Saga Pattern, etc. The corresponding test case looks like below. You’ll want to unit test all of them. But still, we have the flexibility to use the Kafka Client APIs and to add our own flavors to it. Ideally, this section should have been at the beginning. Here’s an example: "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. The problem with those mock classes is that in many cases they … The above 'request' means to do nothing but consume without doing a 'commit'. The @Before will initialize the MockConsumer before each test. 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. Then the methods with @Test annotations are JUnit test methods which will be executed. Once we are done, our full test will look like the code below: And that's it. Designed by Elegant Themes | Powered by WordPress. To run any test(s), we can directly navigate to their corresponding JUnit @Test, under 'src/test/java'. But we must get an idea of what goes inside them. 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. We inject our MockConsumer into the Consumer. The difficult part is some part of the application logic or a DB procedure keeps producing records to a topic and another part of the application keeps consuming the records and continuously processes them based on business rules. Spring Boot Unit Test Simple Example. We can also use Spring Boot instead of using the JUnit framework.. JUnit is one of the testing frameworks used by the Java programmers for creating test cases. 'kafka_test_server.properties' contains the "Broker" details and producer/consumer configs. This results in easier to read test code. This is especially true for your Consumers. The following uses the Junit test case to start a Kafka Server service directly, including four Broker nodes. Unit Tests. I get this exception when I code under test try to consume. That's it. This link is the official tutorial but brand new users may find it hard to run it as the tutorial is not complete and the code has some bugs.. Technologies used in this article are: There are many unit testing frameworks available in Java. 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. Then we use this runner with the @RunWith annotation which will register our JUnit Listener to the test … All gists Back to GitHub Sign in Sign up Sign in Sign up {{ message }} Instantly share code, notes, and snippets. Unit tests make sure that a unit of code is working as expected. The operation, i.e. This code will need to be callable from the unit test. Spring Kafka Test and Embedded Kafka. 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. For now, let's keep it simple and proceed. Note that we set … Like Mockito, JUnit is also an open-source testing framework. the size only, not the actual records. Example: TestNG, JUnit, Mockito, etc. Note: this post was revised in January 20th, 2017 to reflect changes in Kafka. Java JUnit 4 They are the end point for using the data. Also, we can use the Suite runner or Package runner to run the entire test suite. The @Before will initialize the MockProducer before each test. It takes care of instantiating and starting a Kafka Connect server as well as closing it after running your test-case code. While consuming message(s) from the topic, we need to send as below: "request": { }. I hadn’t heard about any deprecation and my quick checks didn’t show any deprecations in the JavaDocs. We can find it here to make everyone's life easy! I talked about that in the post on producers. It in Kafka 1.1. There are often many different Consumers using the data. I’m having same issue of not having MockConsumer updateBeginningOffsets and addRecord(..) ! Or we can mention in our test to do certain things while consuming or after consuming the records. Key-SerDe, Value-SerDe, Time-Outs while record Poolings, commitSyncs, recordTypes, etc., and many more things at the API level. Example Word Count Test without Fluent Kafka Streams Tests. 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 Kafka Streams provides testing utilities to execute unit tests for your stream processing pipelines without having to rely on an external or embedded Kafka cluster. Test using JUnit 5 in your Eclipse IDE. You’ll also need to refactor the code that consumes the data from the Consumer object. 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. The test only fails if the field values or structures don't match. If we have more records, we can set this to a larger value. Furthermore it provides preconfigured consumer settings ( ConsumerSettings consumerDefaults ), A Quick and Practical Example of Kafka Testing, Testing a Kafka Consumer Consuming data from Kafka consists of two main steps. 1. Confluent Developer. Contribute. Sign up for my list so you can get my Professional Data Engineering course. In this tutorial, we are going to see how to write a unit test case by using Mockito and Web Controller. Do I need to use specific version of kafka for unit test? Use promo code CC100KTS to get an additional $100 of free Confluent Cloud - KAFKA TUTORIALS. 1. JUnit 5 integration test with Spring Cloud Stream and embedded Kafka - DemoApplication. ... “By default, JUnit Jupiter tests are run sequentially in a single thread. It passed the tests when I first did the post too. We need to bring up Docker with kafka prior to clicking any Junit tests. Similarly, to write a "consumer" test, we need to know: The topic name 'demo-topic' is our "end point," a.k.a. That's it really. 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. Contents. Java JUnit 4 Well, setting up these properties is not big deal and we have to do this to externalize them anyway. Unit Testing Your Consumer. A JUnit 4 @Rule wrapper for the EmbeddedKafkaBroker is provided to create an embedded Kafka and an embedded Zookeeper server. We learned in the above section how to produce a record and assert the broker response/acknowledgment. Test case. You need to refactor the actual consumption code so it doesn’t get stuck in an infinite loop. For example, when handling credentials or different communication protocols that are determined by the service, it might make sense to abstract that logic from the test code. Assert that the same record was present in the response, i.e. Are you tired of materials that don't go beyond the basics of data engineering. What would you like to do? Note: The comparisons and assertions are instantly done. This helped us to build up and maintain our regression pack in an easy and clean manner. a not-null value. Not only did it compile, but the unit test passed. Postgres or Hadoop). It also provides a rich set of convenient accessors to interact with such an embedded Kafka cluster in a lean and non-obtrusive way. 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. Video includes: How to develop java code to connect Kafka server. You can use whichever method for dependency injection, but I’m making the Consumer public so I can change it from the unit test. Unit testing your Kafka code is incredibly important. It also provides a rich set of convenient accessors to interact with such an embedded Kafka cluster in a lean and non-obtrusive way. 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. Spring-kafka-test provides an embedded Kafka broker. 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. What should we use instead of it? There may be times, for instance, that we validate only the number of records, i.e. 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. Test classes may extend EmbeddedKafkaTest (JUnit 5) or EmbeddedKafkaJunit4Test (JUnit 4) to automatically start and stop an embedded Kafka broker. For functional testing, we don't really need to know these concepts at the API level. Creating an Example Test Case . Apache Kafka; Apache Spark & Scala; Search for: Python Tutorials; 4; Unit Testing With Python Unittest – Example & Working . Refactoring Your Consumers. 1. But, what's the point of just running a docker-compose file without even knowing the outcome of it? This will give us good confidence in releasing our application to higher environments. Are you connecting to broker to get the real message? I strongly recommend reading through the Minimum Things We Need To Know For Kafka Testing post before proceeding with this tutorial. JUnit 5 integration test with Spring Cloud Stream and embedded Kafka - DemoApplication.java 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". EmbeddedKafkaRule. Therefore, we need to cover all API contract validations in our end-to-end test scenarios, including Kafka. This is because the default Kafka PartitionAssignor is the RangeAssignor (see its Javadoc). 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? The test uses a Kafka Consumer to consume events. testCompile "org.springframework.kafka:spring-kafka-test:1.1.2.BUILD-SNAPSHOT" Note that I am using a snapshot version of the project as this has support for Kafka 0.10+. HiveQLUnit is a library of JUnit extensions for unit testing Hive scripts. I just recomplied and reran this exact unit test. Join the DZone community and get the full member experience. This listener can be used for various purposes from improved logging to test specific logic. To write true integration tests you need a real-life Kafka working somewhere to test how your application cooperates with it. @Test(expected = IllegalArgumentException.class) public void testUsernameIsNull() { User user = new User(); user.setName(null); } 3. 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. It's super easy. https://kafka.apache.org/11/javadoc/org/apache/kafka/clients/consumer/MockConsumer.html#updateBeginningOffsets-java.util.Map-. But do you think it's possible to test my Service with this example? In this Python Unittest tutorial, we will learn how to set up unit tests for our Python code. The spring-kafka-test jar contains some useful utilities to assist with testing your applications. In the above "assertions" block, we finished comparing the expected vs. actual values. We call the addRecord() method for every ConsumerRecord we want the Consumer to see. Field  values are reused via JSON path instead of hardcoding. Here we can validate/assert some of the metadata too, but most of the time you might need to deal with the records only (not the metadata). Here we pick a functionality, produce the desired record and validate, consume the intended record and validate, alongside the HTTP REST or SOAP API validation which helps in keeping our tests much cleaner and less noisy. Note: We can even assert all the 'recordMetadata at once, which we will see in the later sections. This is the "assertions" part of our test. This blog post will show how you can setup your Kafka tests to use an embedded Kafka server. When we produce a record to a topic we can verify the acknowledgment from a Kafka broker. Simple Word Count Test. This verification is in the format of recordMetadata. We are writing two test classes below for example only. 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. We can drive our tests also in similar declarative fashion, which we are going to see in next sections. java.lang.IllegalStateException: Subscription to topics, partitions and pattern are mutually exclusive. Can you switch careers to Big Data in 4 months or less? Star 5 Fork 0; Star Code Revisions 2 Stars 5. 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'. consumer.assign(Arrays.asList(topicPartition)); Hi, 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. This rule starts the Kafka and Zookeeper servers on … But it's not a big deal as, after all, nothing changes here, except we just point our "url" to the HTTP endpoint for our REST or SOAP service, then manipulate payload/assertions block accordingly. beginningOffsets.put(topicPartition, 0L); Most of the time in a microservices architecture, we build applications using RESTful services, SOAP services (probably legacy), and Kafka. "pollingTime": 500: Here, we are telling the test to poll for 500 milliseconds each time it polls. In this Apache Kafka tutorial, we will learn that by using Apache JMeter, how to perform Kafka Load Test at Apache Kafka. If you found this page helpful for testing Kafka along with HTTP APIs, please leave a "star" on our Open Source code repo GitHub! 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. 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? Following are … Then we use this runner with the @RunWith annotation which will register our JUnit Listener to the test … I faced the same issue, the workaround for this is to assign new TopicPartition(topic, 0) to a variable and use that. 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. Jesse+ by | Nov 16, 2016 | Blog, Business, Data Engineering, NP | 16 comments. Open pom.xml. 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. You could unit test this way, but I’d prefer mocking for unit tests. For example, a use case could be that I want to see all messages will a specific key in one partition to maintain order. The base class CamelTestSupport has a number of helper methods to configure testing, see more at the javadoc of this class. This means we introduce many challenges in maintaining the test suites along with the bespoke test framework code built inhouse. Visit this page for All configurable keys - ConsumerLocalConfigs from the source code. The creation of the KafkaConsumer should be in separate method that won’t get called by your production Consumer code. But it has a steep learning curve to deal with when it comes to Kafka brokers. consumer.updateBeginningOffsets(beginningOffsets); Please visit these RAW and JSON examples and explanations. EXAMPLE 2: … 'test_kafka_produce.json' is the test case which contains the JSON step(s) we talked about earlier. A great best practice to writing clean and readable JUnit tests is to import static your assert statements. In the following short example, I’d like to show how create a simple setup using Maven, Surefire and kafka-unit. Furthermore it provides preconfigured consumer settings ( ConsumerSettings consumerDefaults ), 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. Hi Jesse, great post I’ve attended your course on Kafka and learned quite a bit. kafka-streams-test-utils ... We need to bring up Docker with kafka prior to clicking any Junit tests. 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. To draw a simile, the interesting way 'docker-compose' works is called the "Declarative Way." acks=1: leader broker added the records to its local log but didn’t wait for any acknowledgment from the followers. JUnit is a simple, powerful, open source framework to write and run repeatable tests. Python Unittesting. Skip to content . This code will need to be callable from the unit test. For instance, when we deal with the brokers, we need to thoroughly get acquainted with the Kafka Client APIs, e.g. But still, we want to be able to test our code somehow without the need to start Zookeeper and Kafka server always. The records, partitions, offsets, exception scenarios, etc. However, if you have an older project you might need to add the spring-kafka-test dependency: org.springframework.kafka spring-kafka-test test Class Configuration JUnit also provide support for adding listeners while executing the tests via RunListener class. 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. How you are verifying the messages wheather consuming correct message or not? Add kafka-streams-test-utils to your project dependencies. We can add this listener by creating a custom Runner. At last, we will see building the Kafka load testing scenario in Jmeter. "url": "url": "kafka-topic: demo-topic". Our test code gets tightly coupled with the client API code. In a previous post, I showed you how to unit test Producers. There are many unit testing frameworks available in Java. For example, visualizing the fetched "records" as JSON would look like below: You need to enable "showRecordsConsumed": true. These tests are fast to run and easy to debug because their scope is small. HashMap beginningOffsets = new HashMap<>(); JUnit RunListener Example 1.1. I mean, using the MockConsumer and MockProducer classes.. Embedded spins up a Kafka cluster. Also, the Consumer object often consumes in an infinite loop (while (true)). I have more dependencies than the one in your sample but are not Kafka related. Create Project Directory Thank you Jesse your blogs have been extremely helpful getting me off the ground. The coverage of my tests is quite low due to differing construction requirements for the mock and concrete implementations but its a start. Kafka call - We send an "Address" record with id "id-lon-123" to the "address-topic," which eventually gets processed and written to  the"Address" database (e.g. It will only read the new messages if any arrive on the topic. In this example we will show you how you can add a JUnit Listener to your test cases. You need to refactor the actual consumption code so it doesn’t get stuck in an infinite loop. The Kafka broker will start before the first test and be stopped after all test classes are finished. All of this is mocked. 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. A Quick and Practical Example of Kafka Testing, Minimum Things We Need To Know For Kafka Testing, All configurable keys - ConsumerLocalConfigs, Developer JUnit 5 integration test with Spring Cloud Stream and embedded Kafka - DemoApplication.java. In this Apache Kafka tutorial, we will learn that by using Apache JMeter, how to perform Kafka Load Test at Apache Kafka. We will use JUnit 5 and Mockito to write the unit test cases. How to use. Just think how much of a hassle it would be if we had to write code/shell scripts for the same repetitive tasks. In the case of RAW, we just say it quietly: 2. There are many ways you can set up such Kafka for testing. In this article, we will learn how to write JUnit test cases for Spring boot REST APIs. This contributes to finding more defects because we don't spend time in writing code, but spend more time in writing tests and covering more business scenarios/user journeys. How neat is that? Moreover, this Kafka load testing tutorial teaches us how to configure the producer and consumer that means developing Apache Kafka Consumer and Kafka Producer using JMeter. Before writing a unit test, we need a test case to implement. 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. Hence it gives us flexibility for covering all kind of test scenarios. Good luck! It’s transporting your most important data. We might have consumed more than one record if they were produced to the same topic before we started consuming. Following code works for me: TopicPartition topicPartition = new TopicPartition(topic, 0); I suggest you try again, actually learn Kafka, learn how to read comments in code, or maybe you need to learn how to code. 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. But we don't have to stop there. You’ve found it. Opinions expressed by DZone contributors are their own. Kafka Load Testing. 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. We can use a JUnit @ClassRule annotation to create this Kafka broker. In your build.sbt file add the following dependency (replace x.x.x with the appropriate version): "io.github.embeddedkafka" %% "embedded-kafka-connect" % "x.x.x" % Test; Have a look at the example test All of the data added by the MockConsumer will be consumed by the Consumer. To write true integration tests you need a real-life Kafka working somewhere to test how your application cooperates with it. Your email address will not be published. In this example we will show you how you can add a JUnit Listener to your test cases. The full record(s) with the meta-data information looks like what we've got below, which we can also validate/assert if we have a test requirement to do so. You’ll want to unit test all of them. Free Python course with 25 projects (coupon code: DATAFLAIR_PYTHON) Start Now. 3)Could I do a unit test without my real consumer? 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. Technologies used in this article are: It's a great time saver! This is great because you will mostly write your code once and read it many times. In this article, we will learn how to write JUnit test cases for Spring boot REST APIs. The most basic test is just to test the integration. This JUnit Listener can listen to events of JUnit lifecycle. 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.. 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. A specialized service factory class is responsible for creating the service according to runtime parameters and/or other test … Once we’ve set the objects up, we can start testing.
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