Function test_python_file_read_buffer

python/pyarrow/tests/test_io.py:219–244

()

def test_python_file_read_buffer():
    length = 10
    data = b'0123456798'
    dst_buf = bytearray(data)

    class DuckReader:
        def close(self):
            pass

        @property
        def closed(self):
            return False

        def read_buffer(self, nbytes):
            assert nbytes == length
            return memoryview(dst_buf)[:nbytes]

    duck_reader = DuckReader()
    with pa.PythonFile(duck_reader, mode='r') as f:
        buf = f.read_buffer(length)
        assert len(buf) == length
        assert memoryview(buf).tobytes() == dst_buf[:length]
        # buf should point to the same memory, so modifying it
        memoryview(buf)[0] = ord(b'x')
        # should modify the original
        assert dst_buf[0] == ord(b'x')


def test_python_file_correct_abc():