Function test_open_append_stream

python/pyarrow/tests/test_fs.py:1099–1120

(fs, pathfn, compression, buffer_size, compressor,
                            decompressor, allow_append_to_file)

    ]
)
def test_open_append_stream(fs, pathfn, compression, buffer_size, compressor,
                            decompressor, allow_append_to_file):
    p = pathfn('open-append-stream')

    initial = compressor(b'already existing')
    with fs.open_output_stream(p) as s:
        s.write(initial)

    if allow_append_to_file:
        with fs.open_append_stream(p, compression=compression,
                                   buffer_size=buffer_size) as f:
            f.write(b'\nnewly added')

        with fs.open_input_stream(p) as f:
            result = f.read()

        result = decompressor(result)
        assert result == b'already existing\nnewly added'
    else:
        with pytest.raises(pa.ArrowNotImplementedError):
            fs.open_append_stream(p, compression=compression,
                                  buffer_size=buffer_size)


def test_open_output_stream_metadata(fs, pathfn):