Is there a way to ‘only’ test the changed grammar.xml from the git root?
Running a single test doesn’t seem to work as described here. It seems you first need to switch to the sub directory and then run the test:
cd languagetool-language-modules/nl
mvn -Dtest=org.languagetool.rules.nl.DutchPatternRuleTest test
If you haven’t done this recently, mvn install -DskipTests
will need to be run first from the LT root.