JUnit-cheatsheet

What is it

This is a set of JUnit tests describing the main JUnit features. Implemented in a form of maven project. (https://maven.apache.org/) The project is properly configured.

For whom this mini guide is intended

A test engineer who has some issues setting it up JUnit5 using Maven.

Tested on

(Windows)

• Maven version: Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
• Java: jdk-11.0.14.101-openj9

(docker maven latest)

• Apache Maven 3.9.6 (bc0240f3c744dd6b6ec2920b3cd08dcc295161ae)

JUnit 5 has different syntax from JUnit 4 This project uses JUnit5

• implementation :org.junit.jupiter 5.10.1

This document describes only configuration, the tests are self-describing.

Configuration

One can easily put in aggregator dependencies in pom.xml and it will work.

    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter</artifactId>
        <version>5.10.1</version>
        <scope>compile</scope>
    </dependency>

Although, it's best to understand what is inside if something goes wrong.
You need two basic components: ENGINE and API. For parameterized tests you need one more component: Params

API - provides basic annotations such as @Test, @BeforeEach, @AfterEach etc

PARAMS - provides annotations to work with parameterized test such as: @ValueSource, @EnumSource, @MethodSource etc.

ENGINE - is a runtime it is responsible for test execution.

In case you use Maven for test execution you need a Maven plugin called Surefire.

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>3.2.3</version>
        </plugin>

In case you plan to use @Suite annotation you need again two components for it

    <dependency>
        <groupId>org.junit.platform</groupId>
        <artifactId>junit-platform-suite-api</artifactId>
        <version>1.10.1</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.platform</groupId>
        <artifactId>junit-platform-suite-engine</artifactId>
        <version>1.10.1</version>
        <scope>test</scope>
    </dependency>

If something does not work - check if a newer version is available first.

the error messages you ll get in these cases unfortunately not very clear. Sometime there is not any messages so you can not understand what you do wrong that is why this project is set up so you could compare it with your configuration

Execution

using docker

1. pull latest maven image docker pull maven
2. interactively run container based on this image and execute a command shell inside docker run -it --name my-maven-container maven bash
3. changes the active directory to one of the current user
   cd
4. Download this repo: git clone https://github.com/ksiv/junit-cheatsheet.git
5. go to 'junit-cheatsheet' folder cd junit-cheatsheet
6. run the tests mvn clean test

This one is easy if you do not have any issues with internet connection like firewall.

Possible issues

1. you have not included all dependencies or have not configured them
2. you put dependencies in the wrong pom.xml section
3. there is a version incompatibility between these dependencies
4. IDE can not download your Maven dependency from a repository in spite of it being correctly configured.
5. you can not download dependencies because there is a firewall on your computer or on ISP level.