Create test_timestamp_fromisoformat.py

pandas/core/apply.py

@@ -651,7 +651,7 @@ def normalize_dictlike_arg(
             and any(is_list_like(v) for _, v in func.items())
         ) or (any(is_dict_like(v) for _, v in func.items())):
             # GH 15931 - deprecation of renaming keys
-            raise SpecificationError("nested renamer is not supported")
+            raise SpecificationError("nested renamer is not supported. Possible duplicate column names.")
 
         if obj.ndim != 1:
             # Check for missing columns on a frame

pandas/tests/scalar/timestamp/test_timestamp_fromisoformat.py

@@ -0,0 +1,18 @@
+import pandas as pd
+import pytest
+# to test and assert that Timestamp.fromisoformat should return a timezone aware timestamp
+
+def test_timestamp_fromisoformat_timezone_handling():
+    # Test case for ISO 8601 string with Zulu (UTC) timezone
+    timestr_utc = '2023-11-05T08:30:00Z'
+    ts_utc = pd.Timestamp.fromisoformat(timestr_utc)
+    assert ts_utc == pd.to_datetime(timestr_utc), "UTC timezone not handled correctly"
+
+    # Test case for ISO 8601 string with the offset timezone
+    timestr_offset = '2023-11-05T08:30:00+0000'
+    ts_offset = pd.Timestamp.fromisoformat(timestr_offset)
+    assert ts_offset == pd.to_datetime(timestr_offset), "Offset timezone not handled correctly"
+
+    # Test case for a roundtrip conversion
+    ts_now = pd.Timestamp.utcnow()
+    assert ts_now == pd.Timestamp.fromisoformat(ts_now.isoformat()), "Roundtrip conversion loses timezone information"