[Feature] Allow copying timezone from Timestamp

Bug: T325864
Change-Id: Ib6aa3c8d96baa21f21bd21030ced0719c2eaa5e2
---
M pywikibot/__init__.py
M tests/wikibase_tests.py
2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/pywikibot/__init__.py b/pywikibot/__init__.py
index 8aea5a8..22c7b38 100644
--- a/pywikibot/__init__.py
+++ b/pywikibot/__init__.py
@@ -574,7 +574,8 @@
                       precision: Union[int, str] = 14,
                       before: int = 0, after: int = 0,
                       timezone: int = 0, calendarmodel: Optional[str] = None,
-                      site: Optional[DataSite] = None) -> 'WbTime':
+                      site: Optional[DataSite] = None,
+                      copy_timezone: bool = False) -> 'WbTime':
         """
         Create a new WbTime object from a pywikibot.Timestamp.
 
@@ -590,7 +591,13 @@
         :param site: The Wikibase site. If not provided, retrieves the data
             repository from the default site from user-config.py.
             Only used if calendarmodel is not given.
+        :param copy_timezone: Whether to copy the timezone from the Timestamp
+            if it has timezone information. Defaults to False to maintain
+            backwards compatibility. If a timezone is given, timezone
+            information is discarded.
         """
+        if not timezone and timestamp.tzinfo and copy_timezone:
+            timezone = int(timestamp.utcoffset().total_seconds() / 60)
         return cls.fromTimestr(timestamp.isoformat(), precision=precision,
                                before=before, after=after,
                                timezone=timezone, calendarmodel=calendarmodel,
diff --git a/tests/wikibase_tests.py b/tests/wikibase_tests.py
index 3bb61e5..6173dd3 100755
--- a/tests/wikibase_tests.py
+++ b/tests/wikibase_tests.py
@@ -490,6 +490,13 @@
         self.assertEqual(t.toTimestamp(), timestamp)
         self.assertEqual(
             t, pywikibot.WbTime.fromTimestamp(timestamp, site=repo))
+        timezone = datetime.timezone(datetime.timedelta(hours=-5))
+        ts = pywikibot.Timestamp(2020, 1, 1, 12, 43, 0, tzinfo=timezone)
+        t = pywikibot.WbTime.fromTimestamp(ts, site=repo, copy_timezone=True)
+        self.assertEqual(t.timezone, -5 * 60)
+        t = pywikibot.WbTime.fromTimestamp(ts, site=repo, copy_timezone=True,
+                                           timezone=60)
+        self.assertEqual(t.timezone, 60)
 
     def test_WbTime_errors(self):
         """Test WbTime precision errors."""

