The aggregator-pipeline artifact contains a Version class, which appears to be completely inoperative.
It's suppose to have several functions. The first is that it's set as the executable class in the .jar, and that is set up correctly. It throws an NPE when invoked, however, which is certainly not intended.
It's also supposed to be able to return a version string for the module, which it doesn't do. Again, the result is an NPE, which appears to be from the static initialisation.
Things are made hard to test (and in particular unit test) because this information is supposed to be extracted from the manifest and this can't be done as part of the build. One way to make things a little better would be to add a --version option to the CLI which could be used to perform a manual test (although invoking the aggregator-pipeline .jar should be equivalent).