BUG: BDay() offsetting not behaving as expected

Author: theoniko

pandas/tests/tseries/offsets/test_offsets.py

@@ -5,6 +5,8 @@
 import numpy as np
 import pytest
 
+import pandas as pd
+
 from pandas._libs.tslibs import (
     NaT,
     OutOfBoundsDatetime,
@@ -2326,6 +2328,74 @@ def test_datetimeindex(self):
         for idx in [idx1, idx2, idx3]:
             tm.assert_index_equal(idx, expected)
 
+    def test_bday_ignores_timedeltas(self):
+        idx = pd.date_range("2010/02/01", "2010/02/15", freq="6H")
+        t1 = idx + BDay(offset=pd.Timedelta(3, unit="H"))
+
+        expected = DatetimeIndex(
+            [
+                "2010-02-02 03:00:00",
+                "2010-02-02 09:00:00",
+                "2010-02-02 15:00:00",
+                "2010-02-02 21:00:00",
+                "2010-02-03 03:00:00",
+                "2010-02-03 09:00:00",
+                "2010-02-03 15:00:00",
+                "2010-02-03 21:00:00",
+                "2010-02-04 03:00:00",
+                "2010-02-04 09:00:00",
+                "2010-02-04 15:00:00",
+                "2010-02-04 21:00:00",
+                "2010-02-05 03:00:00",
+                "2010-02-05 09:00:00",
+                "2010-02-05 15:00:00",
+                "2010-02-05 21:00:00",
+                "2010-02-08 03:00:00",
+                "2010-02-08 09:00:00",
+                "2010-02-08 15:00:00",
+                "2010-02-08 21:00:00",
+                "2010-02-08 03:00:00",
+                "2010-02-08 09:00:00",
+                "2010-02-08 15:00:00",
+                "2010-02-08 21:00:00",
+                "2010-02-08 03:00:00",
+                "2010-02-08 09:00:00",
+                "2010-02-08 15:00:00",
+                "2010-02-08 21:00:00",
+                "2010-02-09 03:00:00",
+                "2010-02-09 09:00:00",
+                "2010-02-09 15:00:00",
+                "2010-02-09 21:00:00",
+                "2010-02-10 03:00:00",
+                "2010-02-10 09:00:00",
+                "2010-02-10 15:00:00",
+                "2010-02-10 21:00:00",
+                "2010-02-11 03:00:00",
+                "2010-02-11 09:00:00",
+                "2010-02-11 15:00:00",
+                "2010-02-11 21:00:00",
+                "2010-02-12 03:00:00",
+                "2010-02-12 09:00:00",
+                "2010-02-12 15:00:00",
+                "2010-02-12 21:00:00",
+                "2010-02-15 03:00:00",
+                "2010-02-15 09:00:00",
+                "2010-02-15 15:00:00",
+                "2010-02-15 21:00:00",
+                "2010-02-15 03:00:00",
+                "2010-02-15 09:00:00",
+                "2010-02-15 15:00:00",
+                "2010-02-15 21:00:00",
+                "2010-02-15 03:00:00",
+                "2010-02-15 09:00:00",
+                "2010-02-15 15:00:00",
+                "2010-02-15 21:00:00",
+                "2010-02-16 03:00:00",
+            ],
+            freq=None,
+        )
+        tm.assert_index_equal(t1, expected)
+
 
 class TestCustomBusinessHour(Base):
     _offset = CustomBusinessHour