Cannot create Launcher without at least one TestEngine; consider adding an engine implementation JAR to the classpath in Junit 5
Solution 1:
Mixing ALPHA snapshot artifacts (i.e., org.junit:junit5-api:5.0.0-SNAPSHOT
) with M2 artifacts (i.e., org.junit.platform:junit-platform-surefire-provider:1.0.0-M2
), won't work.
The Maven section in the user guide suggests to check out the pom.xml
from the junit5-maven-consumer project. If you follow that example, you will end up with something like the following.
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
<junit.jupiter.version>5.0.0-M2</junit.jupiter.version>
<junit.platform.version>1.0.0-M2</junit.platform.version>
</properties>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.19</version>
<dependencies>
<dependency>
<groupId>org.junit.platform</groupId>
<artifactId>junit-platform-surefire-provider</artifactId>
<version>${junit.platform.version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>${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>
</dependencies>
To write your tests, you only need the junit-jupiter-api
; however, in order to run your tests you must have a TestEngine
on the classpath. For JUnit Jupiter you therefore need junit-jupiter-engine
on the classpath as well.
As Nicolai Parlog pointed out, you could add junit-jupiter-engine
as a dependency for the maven-surefire-plugin
; however, that would not include the JupiterTestEngine
in the classpath for your IDE.
If you're only running tests via Maven or with a recent beta version of IntelliJ 2016 (which has built-in support for JUnit 5), then you may not care if JupiterTestEngine
is on the classpath in your IDE. But... if you're using Eclipse, NetBeans, or a non-beta version of IntelliJ, you'll definitely want the JupiterTestEngine
on the classpath in the IDE as well.
Regards,
Sam (core JUnit 5 committer)
Solution 2:
The Maven Surefire plugin not only needs the JUnit 5 provider but also a TestEngine
implementation to run tests with. To quote the JUnit 5 docs:
In order to have Maven Surefire run any tests at all, a
TestEngine
implementation must be added to the runtime classpath.
In accordance with that the following works:
<build>
<plugins>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.19</version>
<dependencies>
<dependency>
<groupId>org.junit.platform</groupId>
<artifactId>junit-platform-surefire-provider</artifactId>
<version>1.0.0-M4</version>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>5.0.0-M4</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>5.0.0-M4</version>
<scope>test</scope>
</dependency>
</dependencies>
Note that this configuration makes the engine a dependency of the surefire plugin, not of your test code.