COMPAT: Added 'Timestamp.fromisocalendar'

Author: MomIsBestFriend

pandas/_libs/tslibs/nattype.pyx

@@ -467,7 +467,14 @@ class NaTType(_NaT):
         Return a new Timestamp representing UTC day and time.
         """
     )
+    fromisocalendar = _make_error_func('fromisocalendar',  # noqa:E128
+        """
+        Timestamp.fromisocalendar(year, week, day)
 
+        Return a new Timestamp corresponding to the
+        ISO calendar date specified by year, week and day.
+        """
+    )
     timestamp = _make_error_func('timestamp',  # noqa:E128
         """Return POSIX timestamp as float.""")
 

pandas/_libs/tslibs/timestamps.pyx

@@ -336,6 +336,23 @@ class Timestamp(_Timestamp):
         """
         return cls(datetime.combine(date, time))
 
+    @classmethod
+    def fromisocalendar(cls, year, week, day):
+        """
+        Timestamp.fromisocalendar(year, week, day)
+
+        Return a new Timestamp corresponding to the
+        ISO calendar date specified by year, week and day.
+        """
+        import pandas.compat as compat
+
+        if not compat.PY38:
+            raise NotImplementedError(
+                "'fromisocalendar' is not supported for versions earlier than 3.8"
+            )
+
+        return cls(datetime.fromisocalendar(year, week, day))
+
     def __new__(
         cls,
         object ts_input=_no_input,

pandas/tests/scalar/test_nat.py

@@ -297,8 +297,6 @@ def test_overlap_public_nat_methods(klass, expected):
     # "fromisoformat" was introduced in 3.7
     if klass is Timestamp and not compat.PY37:
         expected.remove("fromisoformat")
-    if klass is Timestamp and not compat.PY38:
-        expected.remove("fromisocalendar")
 
     assert _get_overlap_public_nat_methods(klass) == expected
 

pandas/tests/scalar/timestamp/test_timestamp.py

@@ -14,6 +14,7 @@
 
 from pandas._libs.tslibs import conversion
 from pandas._libs.tslibs.timezones import dateutil_gettz as gettz, get_timezone
+import pandas.compat as compat
 from pandas.compat.numpy import np_datetime64_compat
 from pandas.errors import OutOfBoundsDatetime
 import pandas.util._test_decorators as td
@@ -700,6 +701,18 @@ class SubDatetime(datetime):
         expected = Timestamp(2000, 1, 1)
         assert result == expected
 
+    @pytest.mark.skipif(
+        not compat.PY38,
+        reason="datetime.fromisocalendar was added in Python version 3.8",
+    )
+    def test_constructor_fromisocalendar(self):
+        # GH 30395
+        expected_timestamp = Timestamp("2000-01-03 00:00:00")
+        expected_stdlib = datetime.fromisocalendar(2000, 1, 1)
+        result = Timestamp.fromisocalendar(2000, 1, 1)
+        assert result == expected_timestamp
+        assert result == expected_stdlib
+
 
 class TestTimestamp:
     def test_tz(self):