In shemagen we have an option

clear ourput dir

http://github.com/dupliaka/run-tests-with-build/blob/RHBOP-8.29.x/run-tests-with-build-sources-download/target/sources/org.optaplanner.optaplanner-8.29.0.Final-redhat-00008/build/optaplanner-build-parent/pom.xml#L541-L541

This plugin clears the output `target` and writes over the META-INF.
If you build the module optaplanner-core-impl from the sources it is fine, but if you dont want to rebuild it and download prebuilt version from RH repo and extract the jar file in the `target/classes` and then run `mvn test` - it will fail bcs schemagen will rewrite the target folder and there would be no items from the RH prebuild artifact.

Affects QE automation.

Steps to reproduce
1. Download sources zip http://download.eng.bos.redhat.com/rcm-guest/staging/rhbop/rhbop-8.29.0.ER1/rhbop-8.29.0-optaplanner-sources.zip
2. Download and unpack to the target/classes optaplanner-core-impl from https://bxms-qe.rhev-ci-vms.eng.rdu2.redhat.com:8443/nexus/content/groups/public-pnc/org/optaplanner/optaplanner-core-impl/8.29.0.Final-redhat-00008/optaplanner-core-impl-8.29.0.Final-redhat-00008.jar
3. at optaplanner-core-impl run mvn test