BUG/TST: dt+BDay(n) wrong if n>5, n%5==0 and dt not on offset (GH5890)

Author: dd137

pandas/tseries/offsets.py

@@ -397,7 +397,9 @@ def apply(self, other):
                 if n < 0 and result.weekday() > 4:
                     n += 1
                 n -= 5 * k
-
+                if n == 0 and result.weekday() > 4:
+                    n -= 1
+            
             while n != 0:
                 k = n // abs(n)
                 result = result + timedelta(k)

pandas/tseries/tests/test_offsets.py

@@ -317,6 +317,11 @@ def test_apply_large_n(self):
         rs = st + off
         xp = datetime(2011, 12, 26)
         self.assertEqual(rs, xp)
+        
+        off = BDay() * 10
+        rs = datetime(2014, 1, 5) + off # see #5890
+        xp = datetime(2014, 1, 17)
+        self.assertEqual(rs, xp)
 
     def test_apply_corner(self):
         self.assertRaises(TypeError, BDay().apply, BMonthEnd())