Eclipse No tests found using JUnit 5 caused by NoClassDefFoundError

The problem

Whenever I run my projects JUnit test (using JUnit 5 with Java 9 and Eclipse Oxygen 1.a) I encounter the problem that eclipse can't find any tests.

The description

Under the run configuration, eclipse can't even find the method which is annotated with @Test, but instead only shows me "(all methods)". The following picture hopefully gives a better glimps of my setup:

Console output:

java.lang.NoClassDefFoundError: org/junit/platform/launcher/core/LauncherFactory
    at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.<init>(JUnit5TestLoader.java:31)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.base/java.lang.reflect.Constructor.newInstance(Unknown Source)
    at java.base/java.lang.Class.newInstance(Unknown Source)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createRawTestLoader(RemoteTestRunner.java:368)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createLoader(RemoteTestRunner.java:363)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.defaultInit(RemoteTestRunner.java:307)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.init(RemoteTestRunner.java:222)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: java.lang.ClassNotFoundException: org.junit.platform.launcher.core.LauncherFactory
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(Unknown Source)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(Unknown Source)
    at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
    ... 11 more

What I tried so far

I've already tried

to remove the test folder from build path and add it again.
to start the test with hovering over the method annotated with @Test and then click "Run as JUnit Test".
remove JUnit from Buildpath and add it again
restart eclipse
I've also moved the project whole project from one machine to another machine and tried it with the provided eclipse installation there
to rename the test method.
to retype the @Test annotation

Some of these steps can be found here, but in the end the problem remained.

You ran into Eclipse bug 525948 which has already been fixed and which will be published in the upcoming release Oxygen.3 (4.7.3), March 21, 2018.

As workaround, put your test code in a separate project and add the project under test to the modulepath, but do not add a module-info.java to your test project. With your project, class and module naming, it should look something like this:

I have the same issue with STS 3.9.1. It seems like an Eclipse bug, however, to fix this you can add a test dependency junit-platform-launcher to your project (https://mvnrepository.com/artifact/org.junit.platform/junit-platform-launcher)

This is how I did for my project which uses gradle:

dependencies {
    // other stuff here

    testCompile group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: "5.${junit5MinorVersion}"
    testCompile group: 'org.junit.platform', name: 'junit-platform-launcher', version: "1.${junit5MinorVersion}"
}

gradle.properties file:

junit5MinorVersion=1.0

I believe the same applies if you see this exception while using IntelliJ IDEA.

stringVector

I fixed the issue by right clicking the test and selecting 'Run Configurations' and changing the "Test runner:" selection to 'JUnit 4' as shown here:

I ran the test again and it worked.

Aldian

Answers so far did not adress the problem of sharing code with other people who don't necessarily use Eclipse. Here is one proposition. The key is to use a maven profile to solve the Eclipse Case.

It assumes you have defined a property junit5.version in your pom like:

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <junit5.version>5.1.1</junit5.version>
</properties>

then in the profiles section add the following:

<profiles>
    <profile>
        <id>eclipse</id>
        <dependencies>
            <dependency>
                <groupId>org.junit.jupiter</groupId>
                <artifactId>junit-jupiter-engine</artifactId>
            </dependency>
            <dependency>
                <groupId>org.junit.platform</groupId>
                <artifactId>junit-platform-launcher</artifactId>
            </dependency>
        </dependencies>
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.junit.jupiter</groupId>
                    <artifactId>junit-jupiter-engine</artifactId>
                    <version>${junit5.version}</version>
                    <scope>test</scope>
                </dependency>
                <dependency>
                    <groupId>org.junit.platform</groupId>
                    <artifactId>junit-platform-launcher</artifactId>
                    <version>1.1.1</version>
                    <scope>test</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    </profile>
</profiles>

All you have to do after this is to select the profile in your local Eclipse: Right click on your project and select Maven > Select Maven Profiles... (or hit Ctrl + Alt + P), and then check the "eclipse" profile we just created.

With that you are done. Your Eclipse will run Junit 5 tests as expected, but the configuration you added won't pollute other builds or other IDE

Following Andrii Karaivanskyi's answer here's the Maven POM declaration:

<properties>
    ...
    <junit-jupiter.version>5.2.0</junit-jupiter.version>
    <junit-platform.version>1.2.0</junit-platform.version>
    ...
</properties>

<dependencies>
    ...
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>${junit-jupiter.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.platform</groupId>
        <artifactId>junit-platform-launcher</artifactId>
        <version>${junit-platform.version}</version>
        <scope>test</scope>
    </dependency>
    ...
</dependencies>

None of the solutions helped:

The problem is that Eclipse 2018-12 has support for JUnit 5.3.1. If you start it with a version before that, it will fail.

So make sure you use at least 5.3.1.

5.4.0 does work too.

In case your parent pom is Spring Boot, you need to make sure (in dependency management) that junit-jupiter-api is set to the same version. You don't need junit-platform-runner or -launcher!

Using STS 3.9.1 I got the same problem. However, currently I do not require any new JUnit5 features, so I tried to force using an older version. If using maven, you can add following dependencies to your pom.xml:

<dependency>
    <groupId>org.junit.platform</groupId>
    <artifactId>junit-platform-launcher</artifactId>
    <version>${junit.platform.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.vintage.version}</version>
    <scope>test</scope>
</dependency>

This did the trick for me (at least as long as I do not need JUnit5 explicitly).

FYI, another cause of "No tests found using junit5" is (inadvertently or intentionally) declaring the test cases "private":

// Example of test case that doesn't get included
@Test
private void testSomeMethod() {
}

They need to be public.

As everyone informed it's IDE bug, I tried in Eclipse and STS. In both the cases, it is failing.

As a workaround, I have fixed by modifying the pom.xml file like below.

I have added these two maven dependencies junit-jupiter-engine and junit-platform-launcher.

pom.xml

<!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-engine -->
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>${junit-jupiter.version}</version>
        <scope>test</scope>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.junit.platform/junit-platform launcher -->
    <dependency>
        <groupId>org.junit.platform</groupId>
        <artifactId>junit-platform-launcher</artifactId>
        <version>${junit-platform.version}</version>
        <scope>test</scope>
    </dependency>
</dependencies>

Also please make sure to add the version of both the maven dependencies in the properties tag.

<properties>
    <java.version>1.8</java.version>
    <junit-jupiter.version>5.2.0</junit-jupiter.version>
    <junit-platform.version>1.2.0</junit-platform.version>
</properties>

In my case, the problem was myself and no IDE like Eclipse. I've imported the JUnit 4 Test class.

So do NOT import this one:

import org.junit.Test  // JUnit 4

But DO import that one:

import org.junit.jupiter.api.Test // JUnit 5

I got the same problem after creating a new TestCase: Eclipse -> New -> JUnit Test Case. It creates a class without access level modifier. I could solve the problem by just putting a public before the class keyword.

Alexander Wessel

Since it's not possible to post code blocks into comments here's the POM template I am using in projects requiring JUnit 5. This allows to build and "Run as JUnit Test" in Eclipse and building the project with plain Maven.

<project
    xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>group</groupId>
    <artifactId>project</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>project name</name>

    <dependencyManagement>
      <dependencies>
        <dependency>
        <groupId>org.junit</groupId>
        <artifactId>junit-bom</artifactId>
        <version>5.3.1</version>
        <type>pom</type>
        <scope>import</scope>
        </dependency>
      </dependencies>
    </dependencyManagement>

    <dependencies>
      <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <scope>test</scope>
      </dependency>

      <dependency>
        <groupId>org.junit.platform</groupId>
        <artifactId>junit-platform-launcher</artifactId>
        <scope>test</scope>
      </dependency>

      <dependency>
        <!-- only required when using parameterized tests -->
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-params</artifactId>
        <scope>test</scope>
      </dependency>
    </dependencies>
</project>

You can see that now you only have to update the version in one place if you want to update JUnit. Also the platform version number does not need to appear (in a compatible version) anywhere in your POM, it's automatically managed via the junit-bom import.

Same error i faced in eclipse version Oxygen.3a Release (4.7.3a) . There is issue in Maven Dependencies mismatch.To solve i have updated my Pom.xml with following dependecies.

http://maven.apache.org/xsd/maven-4.0.0.xsd"> 4.0.0 com.netapp.junitnmactiopractice JunitAndMactioPractice 0.0.1-SNAPSHOT

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>1.8</java.version>
    <junit.jupiter.version>5.1.1</junit.jupiter.version>
    <junit.platform.version>1.1.1</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>
    </plugins>
</build>

<dependencies>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>${junit.jupiter.version}</version>
    </dependency>
    <dependency>
        <groupId>org.junit.platform</groupId>
        <artifactId>junit-platform-runner</artifactId>
        <version>${junit.platform.version}</version>
        <scope>test</scope>
    </dependency>
</dependencies>

Luciano Ortiz

Add in your POM:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.junit</groupId>
            <artifactId>junit-bom</artifactId>
            <version>5.3.1</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Adding this maven dependency with JUnit Jupiter (v.5.5.1) solves the issue.

<dependency>
    <groupId>org.junit.platform</groupId>
    <artifactId>junit-platform-launcher</artifactId>
    <version>1.5.1</version>
    <scope>test</scope>
</dependency>

来源：https://stackoverflow.com/questions/46717693/eclipse-no-tests-found-using-junit-5-caused-by-noclassdeffounderror

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