The Hive build (non-ptest2) uses properties (in the pom.xml) to describe which .q files should be run with minimr versus the normal test runner. All of these .q files exist in the same directory. Therefore without parsing the pom.xml (or build.xml before it) PTest2 has no way to identify which tests should be run via minimr.
At present we do not parse the pom.xml to obtain the list and instead maintain a separate list. The fallout is that when a new minimr test is created, it must added to the properties file for precommit to run it. See Hive PTest2 Infrastructure for the host and path of the properties file to edit.