def METHOD_NAME(self, testdata):
    """
    Test SEISAN file reader with headonly flag.
    """
    # 1 - big endian, 32 bit, version 7
    fn = testdata['9701-30-1048-54S.MVO_21_1']
    st = _read_seisan(fn, headonly=True)
    assert len(st) == 21
    assert st[0].stats.network == ''
    assert st[0].stats.station == 'MBGA'
    assert st[0].stats.location == 'J'
    assert st[0].stats.channel == 'SBZ'
    assert st[0].stats.starttime == \
        UTCDateTime('1997-01-30T10:48:54.040000Z')
    assert st[0].stats.endtime == \
        UTCDateTime('1997-01-30T10:49:42.902881Z')
    assert round(abs(st[0].stats.sampling_rate-75.2), 1) == 0
    assert st[0].stats.npts == 3675
    assert round(abs(st[20].stats.delta-0.0133), 4) == 0
    assert list(st[0].data) == []  # no data
    # 2 - little endian, 32 bit, version 7
    fn = testdata['2001-01-13-1742-24S.KONO__004']
    st = _read_seisan(fn, headonly=True)
    assert len(st) == 4
    assert st[0].stats.network == ''
    assert st[0].stats.station == 'KONO'
    assert st[0].stats.location == '0'
    assert st[0].stats.channel == 'B0Z'
    assert st[0].stats.starttime == \
        UTCDateTime(2001, 1, 13, 17, 45, 1, 999000)
    assert st[0].stats.endtime == \
        UTCDateTime(2001, 1, 13, 17, 50, 1, 949000)
    assert st[0].stats.sampling_rate == 20.0
    assert st[0].stats.npts == 6000
    assert list(st[0].data) == []  # no data
    # 3 - little endian, 32 bit, version 6, 1 channel
    fn = testdata['D1360930.203']
    st = _read_seisan(fn, headonly=True)
    assert len(st) == 1
    assert st[0].stats.network == ''
    assert st[0].stats.station == 'mart'
    assert st[0].stats.location == '1'
    assert st[0].stats.channel == 'cp'
    assert st[0].stats.starttime == UTCDateTime(2017, 7, 22, 9, 30)
    assert st[0].stats.endtime == \
        UTCDateTime(2017, 7, 22, 9, 31, 59, 990000)
    assert st[0].stats.sampling_rate == 100.0
    assert st[0].stats.npts == 12000
    assert list(st[0].data) == []
    # 4 - little endian, 32 bit, version 6, 3 channels
    fn = testdata['2005-07-23-1452-04S.CER___030']
    st = _read_seisan(fn, headonly=True)
    assert len(st) == 3
    assert st[0].stats.channel == 'BHZ'
    assert st[1].stats.channel == 'BHN'
    assert st[2].stats.channel == 'BHE'
    for i in range(0, 3):
        assert st[i].stats.network == ''
        assert st[i].stats.station == 'CER'
        assert st[i].stats.location == ''
        assert st[i].stats.starttime == \
            UTCDateTime('2005-07-23T14:52:04.000000Z')
        assert st[i].stats.endtime == \
            UTCDateTime('2005-07-23T14:53:14.993333Z')
        assert st[i].stats.sampling_rate == 150.0
        assert st[i].stats.npts == 10650
        assert list(st[i].data) == []