datafusion/tests/test_aggregation.py

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import pyarrow as pa
import pytest

from datafusion import SessionContext, column
from datafusion import functions as f


@pytest.fixture
def df():
    ctx = SessionContext()

    # create a RecordBatch and a new DataFrame from it
    batch = pa.RecordBatch.from_arrays(
        [pa.array([1, 2, 3]), pa.array([4, 4, 6])],
        names=["a", "b"],
    )
    return ctx.create_dataframe([[batch]])


def test_built_in_aggregation(df):
    col_a = column("a")
    col_b = column("b")
    df = df.aggregate(
        [],
        [f.max(col_a), f.min(col_a), f.count(col_a), f.approx_distinct(col_b)],
    )
    result = df.collect()[0]
    assert result.column(0) == pa.array([3])
    assert result.column(1) == pa.array([1])
    assert result.column(2) == pa.array([3], type=pa.int64())
    assert result.column(3) == pa.array([2], type=pa.uint64())