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

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from __future__ import annotations

import pyarrow as pa
from datafusion import SessionContext, col, udaf
from datafusion_ffi_example import MySumUDF


def setup_context_with_table():
    ctx = SessionContext()

    # Pick numbers here so we get the same value in both groups
    # since we cannot be certain of the output order of batches
    batch = pa.RecordBatch.from_arrays(
        [
            pa.array([1, 2, 3, None], type=pa.int64()),
            pa.array([1, 1, 2, 2], type=pa.int64()),
        ],
        names=["a", "b"],
    )
    ctx.register_record_batches("test_table", [[batch]])
    return ctx


def test_ffi_aggregate_register():
    ctx = setup_context_with_table()
    my_udaf = udaf(MySumUDF())
    ctx.register_udaf(my_udaf)

    result = ctx.sql("select my_custom_sum(a) from test_table group by b").collect()

    assert len(result) == 2
    assert result[0].num_columns == 1

    result = [r.column(0) for r in result]
    expected = [
        pa.array([3], type=pa.int64()),
        pa.array([3], type=pa.int64()),
    ]

    assert result == expected


def test_ffi_aggregate_call_directly():
    ctx = setup_context_with_table()
    my_udaf = udaf(MySumUDF())

    result = (
        ctx.table("test_table").aggregate([col("b")], [my_udaf(col("a"))]).collect()
    )

    assert len(result) == 2
    assert result[0].num_columns == 2

    result = [r.column(1) for r in result]
    expected = [
        pa.array([3], type=pa.int64()),
        pa.array([3], type=pa.int64()),
    ]

    assert result == expected