Right now, master on coreapps gives the following error on mvn clean test:
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 03:07 min
[INFO] Finished at: 2020-07-20T16:47:03-07:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-dependency-plugin:2.4:unpack-dependencies (Expand moduleApplicationContext and messages) on project coreapps-omod: Error unpacking file: /home/brandon/Code/openmrs-module-coreapps/api/target/classes to: /home/brandon/Code/openmrs-module-coreapps/omod/target/classes
[ERROR] org.codehaus.plexus.archiver.ArchiverException: The source must not be a directory.
[ERROR] -> [Help 1]
Sorry for confusing you. My first time running was with mvn clean install instead of mvn clean test. But it still failed with the exact same error as @bistenes. But on running the same exact command a second time, all was well.