Sharing Test code in Maven

Question

I recommend using type instead of classifier (see also: classifier). It tells Maven a bit more explicitly what you are doing (and I've found that m2eclipse and q4e both like it better).

<dependency>
  <groupId>com.myco.app</groupId>
  <artifactId>foo</artifactId>
  <version>1.0-SNAPSHOT</version>
  <type>test-jar</type>
  <scope>test</scope>
</dependency>

Thanks for the base module suggestion. However, I'd rather not create a new module for just this purpose.

Found an acceptable answer in the Surefire Maven documentation and a blog. See also "How to create a jar containing test classes".

This creates jar file of code from src/test/java using the jar plugin so that modules with tests can share code.

<project>
  <build>
    <plugins>
     <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-jar-plugin</artifactId>
       <version>2.4</version>
       <executions>
         <execution>
           <goals>
             <goal>test-jar</goal>
           </goals>
         </execution>
       </executions>
     </plugin>
    </plugins>
  </build>
</project>

In order to use the attached test JAR that was created above you simply specify a dependency on the main artifact with a specified classifier of tests:

<project>
  ...
  <dependencies>
    <dependency>
      <groupId>com.myco.app</groupId>
      <artifactId>foo</artifactId>
      <version>1.0-SNAPSHOT</version>
      <type>test-jar</type>
      <scope>test</scope>
    </dependency>
  </dependencies>
  ...
</project> 

We solved this by making a maven project with test code as the src/main/java and adding the following dependency to projects:

    <dependency>
        <groupId>foo</groupId>
        <artifactId>test-base</artifactId>
        <version>1</version>
        <scope>test</scope>
    </dependency>