chore: apply suggestions and handle polars exception separately

narwhals/_polars/namespace.py

@@ -120,14 +120,9 @@ def mean_horizontal(self, *exprs: IntoPolarsExpr) -> PolarsExpr:
     def median(self, *column_names: str) -> PolarsExpr:
         import polars as pl  # ignore-banned-import()
 
-        from narwhals._exceptions import InvalidOperationError
         from narwhals._polars.expr import PolarsExpr
 
-        try:
-            return PolarsExpr(pl.median([*column_names]), dtypes=self._dtypes)  # type: ignore[arg-type]
-        except pl.exceptions.InvalidOperationError as e:
-            msg = "`median` operation not supported for non-numeric input type."
-            raise InvalidOperationError(msg) from e
+        return PolarsExpr(pl.median([*column_names]), dtypes=self._dtypes)  # type: ignore[arg-type]
 
     def concat_str(
         self,

tests/expr_and_series/median_test.py

@@ -43,17 +43,22 @@ def test_median_series(
 def test_median_expr_raises_on_str(
     constructor: Constructor,
     expr: nw.Expr,
-    request: pytest.FixtureRequest,
 ) -> None:
-    if "polars" in str(constructor):
-        request.applymarker(pytest.mark.xfail)
+    from polars.exceptions import InvalidOperationError as PlInvalidOperationError
 
     df = nw.from_native(constructor(data))
-    with pytest.raises(
-        InvalidOperationError,
-        match="`median` operation not supported for non-numeric input type.",
-    ):
-        df.select(expr)
+    if "polars_lazy" in str(constructor):
+        with pytest.raises(
+            PlInvalidOperationError,
+            match="`median` operation not supported for dtype `str`",
+        ):
+            df.select(expr).lazy().collect()
+    else:
+        with pytest.raises(
+            (InvalidOperationError, PlInvalidOperationError),
+            match="`median` operation not supported",
+        ):
+            df.select(expr)
 
 
 @pytest.mark.parametrize(("col"), [("s")])