test: fold sum/avg distinct tests into parameterized aggregation test

Move the standalone test_sum_distinct_kwarg and test_avg_distinct_kwarg
from test_functions.py into the existing test_aggregation::test_aggregation
parameterization, matching how distinct is already covered for median,
array_agg, count, and bit_xor.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: timsaucer

python/tests/test_aggregation.py

@@ -192,7 +192,9 @@ def test_aggregation_stats(df, agg_expr, calc_expected):
             False,
         ),
         (f.avg(column("b"), filter=column("a") != lit(1)), pa.array([5.0]), False),
+        (f.avg(column("b"), distinct=True), pa.array([5.0]), False),
         (f.sum(column("b"), filter=column("a") != lit(1)), pa.array([10]), False),
+        (f.sum(column("b"), distinct=True), pa.array([10]), False),
         (f.count(column("b"), distinct=True), pa.array([2]), False),
         (f.count(column("b"), filter=column("a") != 3), pa.array([2]), False),
         (f.count(), pa.array([3]), False),

python/tests/test_functions.py

@@ -1957,36 +1957,6 @@ def test_get_field(df):
     assert result.column(1) == pa.array([4, 5, 6])
 
 
-def test_sum_distinct_kwarg():
-    ctx = SessionContext()
-    df = ctx.from_pydict({"a": [1, 1, 2, 3]})
-    distinct = (
-        df.aggregate([], [f.sum(column("a"), distinct=True).alias("v")])
-        .collect_column("v")[0]
-        .as_py()
-    )
-    total = (
-        df.aggregate([], [f.sum(column("a")).alias("v")]).collect_column("v")[0].as_py()
-    )
-    assert distinct == 6
-    assert total == 7
-
-
-def test_avg_distinct_kwarg():
-    ctx = SessionContext()
-    df = ctx.from_pydict({"a": [1.0, 1.0, 2.0, 3.0]})
-    distinct = (
-        df.aggregate([], [f.avg(column("a"), distinct=True).alias("v")])
-        .collect_column("v")[0]
-        .as_py()
-    )
-    mean = (
-        df.aggregate([], [f.avg(column("a")).alias("v")]).collect_column("v")[0].as_py()
-    )
-    assert distinct == 2.0
-    assert mean == 1.75
-
-
 def test_arrow_metadata():
     ctx = SessionContext()
     field = pa.field("val", pa.int64(), metadata={"key1": "value1", "key2": "value2"})