add a test

python/cudf_polars/cudf_polars/dsl/ir.py

@@ -1139,6 +1139,9 @@ def __init__(
         self.options = options
         self.children = (left, right)
         self._non_child_args = (self.left_on, self.right_on, self.options)
+        # TODO: Implement maintain_order
+        if options[5] != "none":
+            raise NotImplementedError("maintain_order not implemented yet")
         if any(
             isinstance(e.value, expr.Literal)
             for e in itertools.chain(self.left_on, self.right_on)
@@ -1254,8 +1257,7 @@ def do_evaluate(
         right: DataFrame,
     ) -> DataFrame:
         """Evaluate and return a dataframe."""
-        how, join_nulls, zlice, suffix, coalesce, maintain_order = options
-        # TODO: Implement maintain_order param
+        how, join_nulls, zlice, suffix, coalesce, _ = options
         if how == "cross":
             # Separate implementation, since cross_join returns the
             # result, not the gather maps

python/cudf_polars/tests/test_join.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES.
+# SPDX-FileCopyrightText: Copyright (c) 2024-2025, NVIDIA CORPORATION & AFFILIATES.
 # SPDX-License-Identifier: Apache-2.0
 from __future__ import annotations
 
@@ -53,6 +53,15 @@ def right():
     )
 
 
+@pytest.mark.parametrize(
+    "maintain_order", ["left", "left_right", "right_left", "right"]
+)
+def test_join_maintain_order_param_unsupported(left, right, maintain_order):
+    q = left.join(right, on=pl.col("a"), how="inner", maintain_order=maintain_order)
+
+    assert_ir_translation_raises(q, NotImplementedError)
+
+
 @pytest.mark.parametrize(
     "join_expr",
     [