def METHOD_NAME(ftp_writable, cache_type):
    from fsspec.core import BytesCache
    host, port, user, pw = ftp_writable
    files = open_files(
        "ftp:///ou*",
        host=host,
        port=port,
        username=user,
        password=pw,
        block_size=10000,
        cache_type=cache_type,
    )
    assert len(files) == 1
    with files[0] as fo:
        assert fo.read(10) == b"hellohello"
        if isinstance(fo.cache, BytesCache):
            assert len(fo.cache.cache) == 10010
        assert fo.read(2) == b"he"
        assert fo.tell() == 12