Fix time type _arrow_to_datasets_dtype conversion

Author: mariosasko

src/datasets/features/features.py

@@ -78,9 +78,9 @@ def _arrow_to_datasets_dtype(arrow_type: pa.DataType) -> str:
     elif pyarrow.types.is_float64(arrow_type):
         return "float64"  # pyarrow dtype is "double"
     elif pyarrow.types.is_time32(arrow_type):
-        return f"time32[{arrow_type.unit}]"
+        return f"time32[{pa.type_for_alias(str(arrow_type)).unit}]"
     elif pyarrow.types.is_time64(arrow_type):
-        return f"time64[{arrow_type.unit}]"
+        return f"time64[{pa.type_for_alias(str(arrow_type)).unit}]"
     elif pyarrow.types.is_timestamp(arrow_type):
         if arrow_type.tz is None:
             return f"timestamp[{arrow_type.unit}]"

tests/features/test_features.py

@@ -1,3 +1,4 @@
+import datetime
 from dataclasses import asdict
 from unittest import TestCase
 from unittest.mock import patch
@@ -58,6 +59,7 @@ def test_string_to_arrow_bijection_for_primitive_types(self):
             pa.string(),
             pa.int32(),
             pa.float64(),
+            pa.array([datetime.time(1, 1, 1)]).type,  # arrow type: DataType(time64[us])
         ]
         for dt in supported_pyarrow_datatypes:
             self.assertEqual(dt, string_to_arrow(_arrow_to_datasets_dtype(dt)))