Import latest timeutils from oslo-incubator

Fixes bug #1097464

Changes synced are:

 a08daf1 Use basestring instead of str for type check.
 615d769 Account for tasks duration in LoopingCall delay
 ce80aac Convenience wrapper for datetime.timedelta.total_seconds()

Change-Id: If4ab7ccd2f4e815e01c41f25fdd541ffcd7693d5

nova/openstack/common/timeutils.py

@@ -71,14 +71,14 @@ def normalize_time(timestamp):
 
 def is_older_than(before, seconds):
     """Return True if before is older than seconds."""
-    if isinstance(before, str):
+    if isinstance(before, basestring):
         before = parse_strtime(before).replace(tzinfo=None)
     return utcnow() - before > datetime.timedelta(seconds=seconds)
 
 
 def is_newer_than(after, seconds):
     """Return True if after is newer than seconds."""
-    if isinstance(after, str):
+    if isinstance(after, basestring):
         after = parse_strtime(after).replace(tzinfo=None)
     return after - utcnow() > datetime.timedelta(seconds=seconds)
 
@@ -91,22 +91,32 @@ def utcnow_ts():
 def utcnow():
     """Overridable version of utils.utcnow."""
     if utcnow.override_time:
-        return utcnow.override_time
+        try:
+            return utcnow.override_time.pop(0)
+        except AttributeError:
+            return utcnow.override_time
     return datetime.datetime.utcnow()
 
 
 utcnow.override_time = None
 
 
 def set_time_override(override_time=datetime.datetime.utcnow()):
-    """Override utils.utcnow to return a constant time."""
+    """
+    Override utils.utcnow to return a constant time or a list thereof,
+    one at a time.
+    """
     utcnow.override_time = override_time
 
 
 def advance_time_delta(timedelta):
     """Advance overridden time using a datetime.timedelta."""
     assert(not utcnow.override_time is None)
-    utcnow.override_time += timedelta
+    try:
+        for dt in utcnow.override_time:
+            dt += timedelta
+    except TypeError:
+        utcnow.override_time += timedelta
 
 
 def advance_time_seconds(seconds):
@@ -139,3 +149,16 @@ def unmarshall_time(tyme):
                              minute=tyme['minute'],
                              second=tyme['second'],
                              microsecond=tyme['microsecond'])
+
+
+def delta_seconds(before, after):
+    """
+    Compute the difference in seconds between two date, time, or
+    datetime objects (as a float, to microsecond resolution).
+    """
+    delta = after - before
+    try:
+        return delta.total_seconds()
+    except AttributeError:
+        return ((delta.days * 24 * 3600) + delta.seconds +
+                float(delta.microseconds) / (10 ** 6))