def METHOD_NAME(self, mytest, core_filename, run2_suffix):
    """
    Creates a file in rundir2 named CASE2.CORE_FILENAME.nc.RUN2_SUFFIX
    (where CASE2 is the casename of case2)
    Returns full path to the file created
    """
    filename = "{}.{}.nc.{}".format(
        mytest._case2.get_value("CASE"), core_filename, run2_suffix
    )
    filepath = os.path.join(mytest._case2.get_value("RUNDIR"), filename)
    open(filepath, "w").close()
    return filepath