fix: DataFrameGroupby.agg now works with unnamed tuples (#985)

Author: TrevorBergeron

bigframes/core/groupby/__init__.py

@@ -414,12 +414,10 @@ def _agg_named(self, **kwargs) -> df.DataFrame:
                 raise NotImplementedError(
                     f"Only string aggregate names supported. {constants.FEEDBACK_LINK}"
                 )
-            if not hasattr(v, "column") or not hasattr(v, "aggfunc"):
-                import bigframes.pandas as bpd
-
-                raise TypeError(f"kwargs values must be {bpd.NamedAgg.__qualname__}")
-            col_id = self._resolve_label(v.column)
-            aggregations.append((col_id, agg_ops.lookup_agg_func(v.aggfunc)))
+            if not isinstance(v, tuple) or (len(v) != 2):
+                raise TypeError("kwargs values must be 2-tuples of column, aggfunc")
+            col_id = self._resolve_label(v[0])
+            aggregations.append((col_id, agg_ops.lookup_agg_func(v[1])))
             column_labels.append(k)
         agg_block, _ = self._block.aggregate(
             by_column_ids=self._by_col_ids,

tests/system/small/test_groupby.py

@@ -247,6 +247,41 @@ def test_dataframe_groupby_agg_named(scalars_df_index, scalars_pandas_df_index):
     pd.testing.assert_frame_equal(pd_result, bf_result_computed, check_dtype=False)
 
 
+def test_dataframe_groupby_agg_kw_tuples(scalars_df_index, scalars_pandas_df_index):
+    col_names = ["int64_too", "float64_col", "int64_col", "bool_col", "string_col"]
+    bf_result = (
+        scalars_df_index[col_names]
+        .groupby("string_col")
+        .agg(
+            agg1=("int64_too", "sum"),
+            agg2=("float64_col", "max"),
+        )
+    )
+    pd_result = (
+        scalars_pandas_df_index[col_names]
+        .groupby("string_col")
+        .agg(agg1=("int64_too", "sum"), agg2=("float64_col", "max"))
+    )
+    bf_result_computed = bf_result.to_pandas()
+
+    pd.testing.assert_frame_equal(pd_result, bf_result_computed, check_dtype=False)
+
+
+@pytest.mark.parametrize(
+    ("kwargs"),
+    [
+        ({"hello": "world"}),
+        ({"too_many_fields": ("one", "two", "three")}),
+    ],
+)
+def test_dataframe_groupby_agg_kw_error(scalars_df_index, kwargs):
+    col_names = ["int64_too", "float64_col", "int64_col", "bool_col", "string_col"]
+    with pytest.raises(
+        TypeError, match=r"kwargs values must be 2-tuples of column, aggfunc"
+    ):
+        (scalars_df_index[col_names].groupby("string_col").agg(**kwargs))
+
+
 @pytest.mark.parametrize(
     ("as_index"),
     [