diff --git a/.github/workflows/codecov.yml b/.github/workflows/codecov.yml
index e0673d74bda29..296bcc0c96033 100644
--- a/.github/workflows/codecov.yml
+++ b/.github/workflows/codecov.yml
@@ -32,7 +32,7 @@ jobs:
       CARGO_LLVM_COV: 1
       CARGO_LLVM_COV_SHOW_ENV: 1
       CARGO_LLVM_COV_TARGET_DIR: '/Users/runner/work/polars/polars/target'
-      CMAKE_BUILD_PARALLEL_LEVEL: 3
+      CMAKE_BUILD_PARALLEL_LEVEL: 4
 
     steps:
       - uses: actions/checkout@v4
diff --git a/py-polars/tests/unit/test_api.py b/py-polars/tests/unit/test_api.py
index 5b83b53d61fc4..9c1e5ad561c59 100644
--- a/py-polars/tests/unit/test_api.py
+++ b/py-polars/tests/unit/test_api.py
@@ -9,6 +9,8 @@
 
 
 def test_custom_df_namespace() -> None:
+    1 / 0
+
     @pl.api.register_dataframe_namespace("split")
     class SplitFrame:
         def __init__(self, df: pl.DataFrame):