JUnit Examples

Some simple code to show uses of and differences between Junit 4 and 5.

• Content Index

Junit 5 can support JUnit 4

Rather than mix Junit 4 and JUnit 5

I added the JUnit 5 backwards compatibility dependency.

So the following gives JUnit 5 and JUnit 4 direct backwards compatibility:

    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-api</artifactId>
        <version>${junit.jupiter.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>${junit.jupiter.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.vintage</groupId>
        <artifactId>junit-vintage-engine</artifactId>
        <version>${junit.jupiter.version}</version>
        <scope>test</scope>
    </dependency>

Running Both JUnit 4 and JUnit 5 from Command line

The pom.xml

with the addition of surefire plugin:

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.0.0-M4</version>
            </plugin>
        </plugins>
    </build>

Should run both JUnit 4 and Junit 5 on mvn clean test

Explanation Video

Generating an HTML Report for JUnit

And generate an HTML report covering both with mvn clean test site

Add the maven site plugin, (in addition to the surefire plugin) in the build section of pom.xml

   <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-site-plugin</artifactId>
                <version>3.7.1</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.0.0-M4</version>
            </plugin>
        </plugins>
    </build>

And add maven surefire report plugin to the reporting section:

    <!-- `mvn clean test site` to generate the junit html report-->
    <reporting>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-report-plugin</artifactId>
                <version>3.0.0-M4</version>
            </plugin>
        </plugins>
    </reporting>

You can see an example of the generated report here:

• eviltester.github.io/junitexamples/site/index.html
  • this would normally be found in your project as target/site/index.html

Explanation Video

Differences between Junit 4 and JUnit 5

There are many differences between JUnit 4 and 5, in terms of JUnit 5 having more capabilities and different ways of doing stuff.

But there are some very obvious differences between 4 and 5 in terms of:

• ignoring tests
• running methods before and after methods and test classes
• exception asserting

I created two easy to 'diff' example tests with explanation in the project here:

Basic Differences Between 4 and 5