JUnit

lastmod 2024-11-28created 2014-06-0513 edits

Install

To avoid interoperability issues, use Maven Surefire/Failsafe 3.0.0-M4 or later.

Maven

Unless you use Spring Boot, which defines its own way of managing dependencies, it is recommended to use the JUnit Platform BOM to align the versions of all JUnit 5 artifacts.

The following is <dependencyManagement>, not <dependencies>.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.junit</groupId>
            <artifactId>junit-bom</artifactId>
            <version>5.11.3</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Configuring test engines

• JUnit 5 User Guide # Configuring Test Engines

For Maven Surefire or Maven Failsafe to run any tests, at least one TestEngine implementation must be added to the test classpath.

To configure support for JUnit Jupiter based tests, configure test scoped dependencies on the JUnit Jupiter API and the JUnit Jupiter TestEngine implementation similar to the following.

<!-- ... -->
<dependencies>
    <!-- ... -->
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter</artifactId>
        <version>5.11.3</version> <!-- can be omitted when using the BOM -->
        <scope>test</scope>
    </dependency>
    <!-- ... -->
</dependencies>
<build>
    <plugins>
        <plugin>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>3.3.1</version>
        </plugin>
        <plugin>
            <artifactId>maven-failsafe-plugin</artifactId>
            <version>3.3.1</version>
        </plugin>
    </plugins>
</build>
<!-- ... -->

Maven Surefire and Maven Failsafe can run JUnit 4 based tests alongside Jupiter tests as long as you configure test scoped dependencies on JUnit 4 and the JUnit Vintage TestEngine implementation similar to the following.

<!-- ... -->
<dependencies>
    <!-- ... -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.2</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.vintage</groupId>
        <artifactId>junit-vintage-engine</artifactId>
        <version>5.11.3</version> <!-- can be omitted when using the BOM -->
        <scope>test</scope>
    </dependency>
    <!-- ... -->
</dependencies>
<!-- ... -->
<build>
    <plugins>
        <plugin>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>3.3.1</version>
        </plugin>
        <plugin>
            <artifactId>maven-failsafe-plugin</artifactId>
            <version>3.3.1</version>
        </plugin>
    </plugins>
</build>
<!-- ... -->

Simple example

import static org.junit.jupiter.api.Assertions.assertEquals;
import example.util.Calculator;
import org.junit.jupiter.api.Test;

class MyFirstJUnitJupiterTests {
    private final Calculator calculator = new Calculator();

    @Test
    void addition() {
        assertEquals(2, calculator.add(1, 1));
    }
}

JUnit 5

• (Java) How to use JUnit 5 (2) - Introduction, setup, basic methods (@Test, @BeforeEach, @AfterEach, @BeforeAll, @AfterAll, @Disabled)

Unlike previous versions, JUnit 5 consists of three sub-project modules.

JUnit 5 = JUnit Platform + JUnit Jupiter + JUnit Vintage

• JUnit Platform : includes the TestEngine API, Console Launcher, JUnit 4 based Runner, etc.
• JUnit Jupiter : implements JUnit 5 as a TestEngine API implementation
• JUnit Vintage : implements JUnit 3 and 4 as a TestEngine API implementation

Because JUnit 5 includes the JUnit Vintage module, you can use JUnit 3 and 4 syntax. However, it is not fully supported, so extra work is needed if you use it.

Functions

Basic test functions:

• assertEquals(expected, actual)

Annotations

• Google testing blog: Test Sizes

What is the purpose of @SmallTest, @MediumTest, and @LargeTest annotations.

This blog post explains it best. Basically, it is the following:

• Small: this test doesn't interact with any file system or network.
• Medium: Accesses file systems on box which is running tests.
• Large: Accesses external file systems, networks, etc.

Setting up JUnit in intellij and writing simple test code

• (TDD study - java) 1) Setting up JUnit in intellij and writing simple test code

See also

• Android:JUnit: description of JUnit on Android.
• AssertJ

Favorite site

• JUnit 5
• Unit Testing with JUnit - Tutorial ¹
• Using JUnit in Eclipse ²

References