From 4896df23a21a8e7f82c40a975f9d77e1cdeec54c Mon Sep 17 00:00:00 2001
From: FBruzzesi <francesco.bruzzesi.93@gmail.com>
Date: Thu, 12 Sep 2024 23:09:31 +0200
Subject: [PATCH] order matters?

---
 narwhals/_polars/utils.py      | 17 +++++++++--------
 tests/series_only/cast_test.py |  6 +++---
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/narwhals/_polars/utils.py b/narwhals/_polars/utils.py
index dc8696fa6..084651ac9 100644
--- a/narwhals/_polars/utils.py
+++ b/narwhals/_polars/utils.py
@@ -61,14 +61,14 @@ def translate_dtype(dtype: Any) -> dtypes.DType:
         return dtypes.Categorical()
     if dtype == pl.Enum:
         return dtypes.Enum()
-    if isinstance_or_issubclass(dtype, pl.Datetime):
-        time_unit: Literal["us", "ns", "ms"] = getattr(dtype, "time_unit", "us")
-        time_zone = getattr(dtype, "time_zone", None)
-        return dtypes.Datetime(time_unit=time_unit, time_zone=time_zone)
     if dtype == pl.Duration:
         return dtypes.Duration()
     if dtype == pl.Date:
         return dtypes.Date()
+    if isinstance_or_issubclass(dtype, pl.Datetime):
+        time_unit: Literal["us", "ns", "ms"] = getattr(dtype, "time_unit", "us")
+        time_zone = getattr(dtype, "time_zone", None)
+        return dtypes.Datetime(time_unit=time_unit, time_zone=time_zone)
     return dtypes.Unknown()
 
 
@@ -107,12 +107,13 @@ def narwhals_to_native_dtype(dtype: dtypes.DType | type[dtypes.DType]) -> Any:
     if dtype == dtypes.Enum:
         msg = "Converting to Enum is not (yet) supported"
         raise NotImplementedError(msg)
-    if isinstance_or_issubclass(dtype, dtypes.Datetime):
-        time_unit = getattr(dtype, "time_unit", "us")
-        time_zone = getattr(dtype, "time_zone", None)
-        return pl.Datetime(time_unit, time_zone)
     if dtype == dtypes.Duration:
         return pl.Duration()
     if dtype == dtypes.Date:
         return pl.Date()
+    if isinstance_or_issubclass(dtype, dtypes.Datetime):
+        time_unit = getattr(dtype, "time_unit", "us")
+        time_zone = getattr(dtype, "time_zone", None)
+        return pl.Datetime(time_unit, time_zone)
+
     return pl.Unknown()  # pragma: no cover
diff --git a/tests/series_only/cast_test.py b/tests/series_only/cast_test.py
index 37ae55a01..db0242fb5 100644
--- a/tests/series_only/cast_test.py
+++ b/tests/series_only/cast_test.py
@@ -75,13 +75,13 @@ def test_cast_date_datetime_pandas() -> None:
     df = df.select(nw.col("a").cast(nw.Datetime))
     result = nw.to_native(df)
     expected = pd.DataFrame({"a": [datetime(2020, 1, 1), datetime(2020, 1, 2)]}).astype(
-        {"a": "timestamp[ns][pyarrow]"}
+        {"a": "timestamp[us][pyarrow]"}
     )
     pd.testing.assert_frame_equal(result, expected)
 
-    # pandas: pyarrow datetime to date
+    # # pandas: pyarrow datetime to date
     dfpd = pd.DataFrame({"a": [datetime(2020, 1, 1), datetime(2020, 1, 2)]}).astype(
-        {"a": "timestamp[ns][pyarrow]"}
+        {"a": "timestamp[us][pyarrow]"}
     )
     df = nw.from_native(dfpd)
     df = df.select(nw.col("a").cast(nw.Date))