Where should I put interface class for Junit @Cate

I'd like to define project-wide interfaces, to be used in @Category annotations, and configure Maven to exclude their annotated tests when building the whole project.

In the application project there's a test I'd like to categorize:

@Category(Integration.class)
@Test
public void testExternalResource() { ... }

The setting:

I've set up a multi-module maven project:

/container (has a pom with <modules> element)
    /parent (all other modules inherit from its pom. has no source, only pom)
    /util (other modules are depending on it)
    /infra
    /application (depending on infra and util, inherits from parent)

Being an infrastructure freak :), I'd like to configure my whole project to exclude groups in any module. So, in parent module I've defined:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.16</version>
    <configuration>
         <excludedGroups>com.mycompany.test.Integration</excludedGroups>
    </configuration>
</plugin>

And I've put the Integration interface in the util module (in the util/src/test/java), for all modules to see:

package com.mycompany.test;
public interface Integration {}

And because it's a test-jar, I've made the right configuration for both util and application .

The error:

When running mvn clean install, I'm getting

[ERROR] Failed to execute goal org.apache.maven.plugins:
    maven-surefire-plugin:2.16:test
    (default-test) on project util: Execution default-test of goal
    org.apache.maven.plugins:maven-surefire-plugin:2.16:test
    failed: There was an error in the forked process
[ERROR] java.lang.RuntimeException:
    Unable to load category: com.mycompany.test.Integration

Well, of course the class isn't available - I've crammed it in a test-jar in the first module of the project. :(

Where should I put my Integration interface so it will be available to my mvn configuration and my source code?

Create a new Maven module and put the interface under src/main/java/. Make sure junit is available as a compile time dependency (<scope>compile</scope>) - you're basically building a dependency that other tests can use. So your code that helps other tests must go into main while the tests for this go in the src/test/java, as usual.

This step feels a bit weird but think about how you would package junit itself. From the point of view of junit, it's just a normal Java library, so all its code goes into main.

When you need this module, use it as a test dependency with <scope>test</scope>