We have a number of test classes that use the org.testng.annotations.Factory annotation to provide the testcases:

import org.testng.annotations.Factory;
import eu.educator.test.TestBuilder;

public class LogEntryTest {
	@Factory
	public Object[] testLogEntry() {
		TestBuilder builder = new TestBuilder(Dummy.class);
		// stuff...
		return builder.build();
	}
}

These are not picked up by the gradle testng testcase scanner. (they are completely left out of the test classes that are run)

Workarounds are to include an additional @Test annotation on the class itself. Or set scanForTestClasses = false, and provide a proper include pattern.