def METHOD_NAME(self, filename, filename_info, filetype_info):
    """Mimic reader input file content."""
    from xarray import DataArray
    dt_s = filename_info.get('start_time', datetime(2019, 6, 19, 13, 0))
    dt_e = filename_info.get('end_time', datetime(2019, 6, 19, 13, 0))
    if filetype_info['file_type'] == 'mimicTPW2_comp':
        file_content = {
            '/attr/start_time': dt_s.strftime('%Y%m%d.%H%M%S'),
            '/attr/end_time': dt_e.strftime('%Y%m%d.%H%M%S'),
            '/attr/platform_shortname': 'aggregated microwave',
            '/attr/sensor': 'mimic',
        }
        file_content['latArr'] = DEFAULT_LAT
        file_content['latArr/shape'] = (DEFAULT_FILE_SHAPE[0],)
        file_content['latArr/attr/units'] = 'degress_north'
        file_content['lonArr'] = DEFAULT_LON
        file_content['lonArr/shape'] = (DEFAULT_FILE_SHAPE[1],)
        file_content['lonArr/attr/units'] = 'degrees_east'
        file_content['tpwGrid'] = DEFAULT_FILE_DATA
        file_content['tpwGrid/shape'] = DEFAULT_FILE_SHAPE
        file_content_units['tpwGrid'] = 'mm'
        file_content['/dimension/lat'] = DEFAULT_FILE_SHAPE[0]
        file_content['/dimension/lon'] = DEFAULT_FILE_SHAPE[1]
        # convert to xarrays
        for key, val in file_content.items():
            if key == 'lonArr' or key == 'latArr':
                file_content[key] = DataArray(val)
            elif isinstance(val, np.ndarray):
                if val.ndim > 1:
                    file_content[key] = DataArray(val, dims=('y', 'x'), attrs={"units": file_content_units[key]})
                else:
                    file_content[key] = DataArray(val)
    else:
        msg = 'Wrong Test Reader for file_type {}'.format(filetype_info['file_type'])
        raise AssertionError(msg)
    return file_content