fix: PySpark like tests (#2562)

* fix: PySpark like tests

* try casting to float

* forgot casting callspec id

Author: FBruzzesi

narwhals/_spark_like/expr.py

@@ -816,7 +816,7 @@ def _log(_input: Column) -> Column:
             return (
                 self._F.when(_input < 0, self._F.lit(float("nan")))
                 .when(_input == 0, self._F.lit(float("-inf")))
-                .otherwise(self._F.log(base, _input))
+                .otherwise(self._F.log(float(base), _input))
             )
 
         return self._with_callable(_log)

narwhals/functions.py

@@ -24,7 +24,6 @@
 from narwhals.dependencies import is_pyarrow_table
 from narwhals.exceptions import InvalidOperationError
 from narwhals.expr import Expr
-from narwhals.series import Series
 from narwhals.translate import from_native
 from narwhals.translate import to_native
 from narwhals.utils import Implementation

tests/expr_and_series/skew_test.py

@@ -34,6 +34,7 @@ def test_skew_series(
         ([0.0, 0.0, 0.0], None),
         ([1, 2, 3, 2, 1], 0.343622),
     ],
+    ids=range(5),
 )
 @pytest.mark.filterwarnings("ignore:.*invalid value:RuntimeWarning:dask")
 def test_skew_expr(
@@ -45,5 +46,10 @@ def test_skew_expr(
     if "ibis" in str(constructor):
         # https://github.com/ibis-project/ibis/issues/11176
         request.applymarker(pytest.mark.xfail)
+
+    if "pyspark" in str(constructor) and int(request.node.callspec.id[-1]) == 0:
+        # Can not infer schema from empty dataset.
+        pytest.skip()
+
     result = nw.from_native(constructor({"a": data})).select(nw.col("a").skew())
     assert_equal_data(result, {"a": [expected]})