TST: add basic test for construction with fold

Author: AlexKirko

pandas/_libs/tslibs/timestamps.pyx

@@ -351,7 +351,8 @@ class Timestamp(_Timestamp):
         second=None,
         microsecond=None,
         nanosecond=None,
-        tzinfo=None
+        tzinfo=None,
+        fold=None
     ):
         # The parameter list folds together legacy parameter names (the first
         # four) and positional and keyword parameter names from pydatetime.

pandas/tests/indexes/datetimes/test_constructors.py

@@ -964,3 +964,13 @@ def test_timestamp_constructor_identity():
     expected = pd.Timestamp("2017-01-01T12")
     result = pd.Timestamp(expected)
     assert result is expected
+
+
+@pytest.mark.parametrize("tz", ["dateutil/Europe/London", "Europe/London"])
+@pytest.mark.parametrize("fold", [0, 1])
+def test_timestamp_constructor_fold(tz, fold):
+    # Test for #25057
+    ts = pd.Timestamp(year=2019, month=10, day=27, hour=1, minute=30, tz=tz, fold=fold)
+    result = ts.fold
+    expected = fold
+    assert result == expected