From 3685fd54f933e4c7279615f5c463c214a02eac75 Mon Sep 17 00:00:00 2001
From: Tan Tran <42478131+tranctan@users.noreply.github.com>
Date: Wed, 11 Dec 2019 18:21:30 +0700
Subject: [PATCH] TST: DataFrameGroupBy.shift Loses TimeZone in datetime64
 columns (#30153)

---
 pandas/tests/groupby/test_groupby.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/pandas/tests/groupby/test_groupby.py b/pandas/tests/groupby/test_groupby.py
index 3a16642641fca3..93d4dc6046735a 100644
--- a/pandas/tests/groupby/test_groupby.py
+++ b/pandas/tests/groupby/test_groupby.py
@@ -1702,6 +1702,15 @@ def test_group_shift_with_fill_value():
     tm.assert_frame_equal(result, expected)
 
 
+def test_group_shift_lose_timezone():
+    # GH 30134
+    now_dt = pd.Timestamp.utcnow()
+    df = DataFrame({"a": [1, 1], "date": now_dt})
+    result = df.groupby("a").shift(0).iloc[0]
+    expected = Series({"date": now_dt}, name=result.name)
+    tm.assert_series_equal(result, expected)
+
+
 def test_pivot_table_values_key_error():
     # This test is designed to replicate the error in issue #14938
     df = pd.DataFrame(