add test for validate_all_hashable

Author: topper-123

pandas/core/dtypes/common.py

@@ -9,7 +9,7 @@
 
 from pandas._libs import Interval, Period, algos
 from pandas._libs.tslibs import conversion
-from pandas._typing import ArrayLike, DtypeObj
+from pandas._typing import ArrayLike, DtypeObj, Optional
 
 from pandas.core.dtypes.base import registry
 from pandas.core.dtypes.dtypes import (
@@ -1732,7 +1732,7 @@ def _validate_date_like_dtype(dtype) -> None:
         )
 
 
-def validate_all_hashable(*args, error_name=None) -> None:
+def validate_all_hashable(*args, error_name: Optional[str] = None) -> None:
     """
     Return None if all args are hashable, else raise a TypeError.
 

pandas/tests/dtypes/test_common.py

@@ -746,3 +746,13 @@ def test_astype_object_preserves_datetime_na(from_type):
     result = astype_nansafe(arr, dtype="object")
 
     assert isna(result)[0]
+
+
+def test_validate_allhashable():
+    assert com.validate_all_hashable(1, "a") is None
+
+    with pytest.raises(TypeError, match="All elements must be hashable"):
+        com.validate_all_hashable([])
+
+    with pytest.raises(TypeError, match="list must be a hashable type"):
+        com.validate_all_hashable([], error_name="list")