Embedded Kafka for Spring Boot Testing without using Docker

Wed, 25 May 2022 00:00:00 +0200

Sometimes it is nice to set up an embedded Kafka broker for testing without the need to have Docker installed (e.g. for using testcontainers-lib).

The following snippet shows, how to set up an embedded Kafka instance for testing for a Spring Boot project.

Setup

Using Maven, this is our Spring Boot project with dependencies needed:

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>(1)
        <version>2.6.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.hascode.tutorial</groupId>
    <artifactId>kafka-testing</artifactId>
    <version>1.0.0-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>17</java.version>
        <maven.compiler.source>${java.version}</maven.compiler.source>
        <maven.compiler.target>${java.version}</maven.compiler.target>
        <kafka.version>3.1.0</kafka.version>(2)
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>(3)
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka-test</artifactId>(4)
            <scope>test</scope>
        </dependency>

        <dependency>(5)
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-engine</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.platform</groupId>
            <artifactId>junit-platform-launcher</artifactId>
            <scope>test</scope>
        </dependency>
        [..]
</project>

JUnit5 Java Maven Snippet

Fri, 14 May 2021 00:00:00 +0200

Goals

Use JUnit Maven BOM for version alignment
Add minimal dependencies for JUnit5 Java Projekt

Setup

Excerpt from the Maven project’s pom.xml:

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.junit</groupId>
      <artifactId>junit-bom</artifactId>
      <version>5.7.1</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter</artifactId>
    <scope>test</scope>
  </dependency>
</dependencies>

JUnit5 does not work with older versions of the Maven Compiler Plugin and the Surefire Plugin used for test execution. Setting their versions in the pom.xml is done like this:

Using Throwaway Containers for Integration Testing with Java, JUnit 5 and Testcontainers.

Wed, 30 Jan 2019 00:00:00 +0100

A lot of boilerplate code is written when developers need to test their applications with different connected systems like databases, stream platforms and other collaborators.

Docker allows to handle those dependencies but there is still some glue code required to bind the container’s lifecycle and the configuration to the concrete integration test.

Testcontainers is a testing library that offers lightweight throwaway instances of anything able to run in a Docker container, with bindings to configure the specific containers and also provides wrappers to manage our own custom containers.

Using JUnit 5 Parameterized Tests, Argument Sources and Converters

Sat, 19 Aug 2017 00:00:00 +0200

With JUnit 5 the possibilities to write parameterized tests have changed and improved a lot.

The following short overview covers all new types of possible parameter sources for JUnit 5 tests as well as the new conversion API for test arguments.

In addition we’re showing how parameterized tests were written in JUnit 4.

Figure 1. Running JUnit5 in IntelliJ

About

We will be covering all available types of parameter sources in the following sections – all that you need as a prerequisite is Java ™, Maven and a few minutes of your time.

IntelliJ Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Live Templates

JUnit 5 Test

@org.junit.jupiter.api.Test

@org.junit.jupiter.api.DisplayName("$NAME$")

void $METHOD$() throws Exception {

    $END$

}

Figure 1. IntelliJ Live Template Editor

Edit Variables:

NAME
METHOD: default-value camelCase(NAME)

Figure 2. Editing template variables

SLF4J Logger Template

private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger( $CLASS$.class );

Edit variables:

CLASS: expression: className()

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Cmd+Shift+C

Java Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Remote Debug a Pod’s Java Process

Simple steps for remote debugging a Java process running on a k8 pod:

Edit deployment and add the following parameters to the Java start line: -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=127.0.0.1:5005

Also add the following port mapping at the section container → ports in the deployment:
```
- containerPort: 5005
  protocol: TCP
```
Safe, wait for the new pods and then add a port forward for port 5005 for this pod:
```
kubectl port-forward podname 5005
```

Junit5 on Micha Kops' Tech Notes

Embedded Kafka for Spring Boot Testing without using Docker

Setup

JUnit5 Java Maven Snippet

Setup

Using Throwaway Containers for Integration Testing with Java, JUnit 5 and Testcontainers.

Using JUnit 5 Parameterized Tests, Argument Sources and Converters

About

IntelliJ Snippets

Live Templates

JUnit 5 Test

SLF4J Logger Template

Favorite Shortcuts

Select whole block in Editor

Select similar blocks in editor

Copy the absolute Path of the current File into Clipboard

Java Snippets

Remote Debug a Pod’s Java Process