Yep ... just include the Base module as a dependency in Main. If you're only inheriting test code, then you can use the scope tag to make sure Maven doesn't include the code in your artifact when deployed. Something like this should work:
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:
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).
Worked for me for 1 project, but I didn't for another after doing exactly the same steps.
So I debugged:
After mvn clean install I checked /target directory: .jar was there so thats good
Ran mvn dependency:tree on a project which should use those test classes. Noticed that generated jar file with test classes is marked as dependency, so thats good.
Conclusion could be only one - I restarted my Intellj. At first class import was still not visible, but after a minute it started to see it!
Note: I only restarted Intellj, no caches removal etc