Question

I’m trying to create a JAR that I can put on a non development machine and run some unit tests that exercise a web service. I’ve read that there are many ways to do this in maven. I’m focusing on using the test-jar goal because that seems the most logical approach.

My tests are in a separate maven project with a folder structure of:

/myProject/src/test/java/org/testplatform/services/test/<name of testng test>.java

Here is my config for the test-jar in the pom:

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <executions>
              <execution>
                <goals>
                  <goal>test-jar</goal>
                </goals>
              </execution>
            </executions>
            <configuration>
                <archive>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <mainClass>org/testplatform/services/test/MainTestClass.java</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>

When I execute the resulting JAR I get this error:

Exception in thread "main" java.lang.NoClassDefFoundError: org/testng/ITestListener
Caused by: java.lang.ClassNotFoundException: org.testng.ITestListener
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

Can someone help me understand what changes I need to make in my pom and/or tests to create an independent, executable JAR for running testng unit tests? A demo project would be helpful.

Answer 1

The error is suggesting that you are using TestNG classes and that these aren’t available in the resulting classpath. This is possible because you test scoped your testNG dependency

<dependency>
  <groupId>...</groupId>
  <artifactId>...</artifactId>
  <version>...</version>
  <scope>test</scope>           <<< Test scope
</dependency>

This will result in the exclusion of this dependency from the resulting JAR.

In case you haven’t already, I suggest reading Maven’s in-depth explanation of the recommended way of building a test JAR and the pitfalls to avoid.

You have the made the correct step of extracting your test classes to a separate project. This ensures that you can leverage Maven’s transitive dependencies. You also need to move dependencies out of test scope.