Cannot create Launcher without at least one TestEngine; consider adding an engine implementation JAR to the classpath in Junit 5
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)
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
TestEngineimplementation 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.