Add test case for bottom_k() descending=True with no by

py-polars/tests/unit/operations/test_sort.py

@@ -300,6 +300,11 @@ def test_top_k() -> None:
         pl.DataFrame({"test": [1, 2, 3, 4]}),
     )
 
+    assert_frame_equal(
+        df.select(pl.col("test").bottom_k(10, descending=True)),
+        pl.DataFrame({"test": [4, 3, 2, 1]}),
+    )
+
     assert_frame_equal(
         df.select(
             top_k=pl.col("test").top_k(pl.col("val").min()),