examples/datafusion-ffi-example/python/tests/_test_table_provider.py

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from __future__ import annotations

import pyarrow as pa
from datafusion import SessionContext
from datafusion_ffi_example import MyTableProvider


def test_table_loading():
    ctx = SessionContext()
    table = MyTableProvider(3, 2, 4)
    ctx.register_table("t", table)
    result = ctx.table("t").collect()

    assert len(result) == 4
    assert result[0].num_columns == 3

    result = [r.column(0) for r in result]
    expected = [
        pa.array([0, 1], type=pa.int32()),
        pa.array([2, 3, 4], type=pa.int32()),
        pa.array([4, 5, 6, 7], type=pa.int32()),
        pa.array([6, 7, 8, 9, 10], type=pa.int32()),
    ]

    assert result == expected

    result = ctx.read_table(table).collect()
    result = [r.column(0) for r in result]
    assert result == expected