The callers of LayersTest.test maintain sets of expected unused or unreferenced modules that they pass into test. The test uses those to check whether any unused or unreferenced module were unexpected. The test should be enhanced to do the opposite as well – see if modules that were expected to be unused or unreferenced 1) exist and 2) actually were unused or unreferenced. Doing this will ensure that the test expectations are maintained along with the software.

This should probably not be the default behavior, but instead be enabled via system property. This will avoid the problem of changes in core causing failures in full until core is upgraded. Pull request CI for core itself can run with the property set; for full WF it can be set on a nightly job.