Edit comments and tests

Author: Si Wei How

pandas/tests/tseries/offsets/test_offsets.py

@@ -769,19 +769,31 @@ def setup_method(self, method):
 
     def test_constructor_errors(self):
         from datetime import time as dt_time
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError,
+                           match='time data must be specified only with hour and minute'):
             BusinessHour(start=dt_time(11, 0, 5))
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError,
+                           match="time data must match '%H:%M' format"):
             BusinessHour(start='AAA')
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError,
+                           match="time data must match '%H:%M' format"):
             BusinessHour(start='14:00:05')
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError,
+                           match='number of starting time cannot be 0'):
             BusinessHour(start=[])
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError,
+                           match='number of ending time cannot be 0'):
+            BusinessHour(end=[])
+        with pytest.raises(ValueError,
+                           match='number of starting time and ending time '
+                                 'must be the same'):
             BusinessHour(start=['09:00', '11:00'])
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError,
+                           match='number of starting time and ending time '
+                                 'must be the same'):
             BusinessHour(start=['09:00', '11:00'], end=['10:00'])
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError,
+                           match=r'invalid starting and ending time\(s\)'):
             BusinessHour(start=['09:00', '11:00'], end=['12:00', '20:00'])
 
     def test_different_normalize_equals(self):

pandas/tseries/offsets.py

@@ -582,10 +582,14 @@ def __init__(self, start='09:00', end='17:00', offset=timedelta(0)):
         # must be validated here to equality check
         if _iterable_not_string(start):
             start = np.asarray(start)
+            if len(start) == 0:
+                raise ValueError('number of starting time cannot be 0')
         else:
             start = np.array([start])
         if _iterable_not_string(end):
             end = np.asarray(end)
+            if len(end) == 0:
+                raise ValueError('number of ending time cannot be 0')
         else:
             end = np.array([end])
 
@@ -595,7 +599,7 @@ def __init__(self, start='09:00', end='17:00', offset=timedelta(0)):
 
         # Validation of input
         if len(start) != len(end):
-            raise ValueError('number of starting time and ending time'
+            raise ValueError('number of starting time and ending time '
                              'must be the same')
         num_openings = len(start)
 
@@ -639,15 +643,17 @@ def _get_daytime_flag(self, start, end):
 
     def _next_opening_time(self, other, dir=1):
         """
-        If n is positive, return tomorrow's business day opening time.
-        Otherwise yesterday's business day's opening time.
+        If self.n and dir have the same sign, return the earliest opening time
+        later than or equal to current time.
+        Otherwise the latest opening time earlier than or equal to current time.
 
         Opening time always locates on BusinessDay.
-        Otherwise, closing time may not if business hour extends over midnight.
+        However, closing time may not if business hour extends over midnight.
         """
         earliest_start = self.start[0]
         latest_start = self.start[-1]
         if not self.next_bday.onOffset(other):
+            # today is not business day
             other = other + dir * self.next_bday
             if self.n * dir >= 0:
                 return datetime(other.year, other.month, other.day,
@@ -657,28 +663,34 @@ def _next_opening_time(self, other, dir=1):
                                 latest_start.hour, latest_start.minute)
         else:
             if self.n * dir >= 0 and latest_start < other.time():
+                # current time is after latest starting time in today
                 other = other + dir * self.next_bday
                 return datetime(other.year, other.month, other.day,
                                 earliest_start.hour, earliest_start.minute)
             elif self.n * dir < 0 and other.time() < earliest_start:
+                # current time is before earliest starting time in today
                 other = other + dir * self.next_bday
                 return datetime(other.year, other.month, other.day,
                                 latest_start.hour, latest_start.minute)
         if self.n * dir >= 0:
+            # find earliest starting time later than or equal to current time
             for st in self.start:
                 if other.time() <= st:
                     return datetime(other.year, other.month, other.day,
                                     st.hour, st.minute)
         else:
+            # find latest starting time earlier than or equal to current time
             for st in reversed(self.start):
                 if other.time() >= st:
                     return datetime(other.year, other.month, other.day,
                                     st.hour, st.minute)
 
     def _prev_opening_time(self, other):
         """
-        If n is positive, return yesterday's business day opening time.
-        Otherwise yesterday business day's opening time.
+        If n is positive, return the latest opening time earlier than or equal
+        to current time.
+        Otherwise the earliest opening time later than or equal to current time.
+
         """
         return self._next_opening_time(other, dir=-1)