Add nova time util functions to timeutils

Fixes bug #1009410

1. Add the following functions from nova/utils.py
- strtime
- parse_strtime
- is_older_than
- utcnow_ts
- advance_time_delta
- advance_time_seconds

2. Write unittests in tests/unit/test_timeutils.py

Change-Id: Ie0bba90833e2ed31bb5ab867a7c1a76a9901cacb

2 files changed, 89 insertions, 10 deletions

diff --git a/openstack/common/timeutils.py b/openstack/common/timeutils.py
index 345f315..a7b2ce3 100644
--- a/openstack/common/timeutils.py
+++ b/openstack/common/timeutils.py
@@ -20,11 +20,13 @@ Time related utilities and helper functions.
 """
 
 import datetime
+import time
 
 import iso8601
 
 
 TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
+PERFECT_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%f"
 
 
 def isotime(at=None):
@@ -47,12 +49,34 @@ def parse_isotime(timestr):
         raise ValueError(e.message)
 
 
+def strtime(at=None, fmt=PERFECT_TIME_FORMAT):
+    """Returns formatted utcnow."""
+    if not at:
+        at = utcnow()
+    return at.strftime(fmt)
+
+
+def parse_strtime(timestr, fmt=PERFECT_TIME_FORMAT):
+    """Turn a formatted time back into a datetime."""
+    return datetime.datetime.strptime(timestr, fmt)
+
+
 def normalize_time(timestamp):
     """Normalize time in arbitrary timezone to UTC"""
     offset = timestamp.utcoffset()
     return timestamp.replace(tzinfo=None) - offset if offset else timestamp
 
 
+def is_older_than(before, seconds):
+    """Return True if before is older than seconds."""
+    return utcnow() - before > datetime.timedelta(seconds=seconds)
+
+
+def utcnow_ts():
+    """Timestamp version of our utcnow function."""
+    return time.mktime(utcnow().timetuple())
+
+
 def utcnow():
     """Overridable version of utils.utcnow."""
     if utcnow.override_time:
@@ -68,6 +92,17 @@ def set_time_override(override_time=datetime.datetime.utcnow()):
     utcnow.override_time = override_time
 
 
+def advance_time_delta(timedelta):
+    """Advance overriden time using a datetime.timedelta."""
+    assert(not utcnow.override_time is None)
+    utcnow.override_time += timedelta
+
+
+def advance_time_seconds(seconds):
+    """Advance overriden time by seconds."""
+    advance_time_delta(datetime.timedelta(0, seconds))
+
+
 def clear_time_override():
     """Remove the overridden time."""
     utcnow.override_time = None
diff --git a/tests/unit/test_timeutils.py b/tests/unit/test_timeutils.py
index 59a5032..ba68235 100644
--- a/tests/unit/test_timeutils.py
+++ b/tests/unit/test_timeutils.py
@@ -26,21 +26,55 @@ from openstack.common import timeutils
 
 class TimeUtilsTest(unittest.TestCase):
 
-    def test_isotime(self):
-        skynet_self_aware_time_str = '1997-08-29T06:14:00Z'
-        skynet_self_aware_time = datetime.datetime(1997, 8, 29, 6, 14, 0,
+    def setUp(self):
+        utc_timezone = iso8601.iso8601.UTC
+        self.skynet_self_aware_time_str = '1997-08-29T06:14:00Z'
+        self.skynet_self_aware_time = datetime.datetime(1997, 8, 29, 6, 14, 0,
+                                                        tzinfo=utc_timezone)
+        self.one_minute_before = datetime.datetime(1997, 8, 29, 6, 13, 0,
                                                    tzinfo=iso8601.iso8601.UTC)
+        self.skynet_self_aware_time_perfect_str = '1997-08-29T06:14:00.000000'
+        self.skynet_self_aware_time_perfect = datetime.datetime(1997, 8, 29,
+                                                                6, 14, 0)
+
+    def tearDown(self):
+        timeutils.clear_time_override()
+
+    def test_isotime(self):
         with mock.patch('datetime.datetime') as datetime_mock:
-            datetime_mock.utcnow.return_value = skynet_self_aware_time
+            datetime_mock.utcnow.return_value = self.skynet_self_aware_time
             dt = timeutils.isotime()
-            self.assertEqual(dt, skynet_self_aware_time_str)
+            self.assertEqual(dt, self.skynet_self_aware_time_str)
 
     def test_parse_isotime(self):
-        skynet_self_aware_time_str = '1997-08-29T06:14:00Z'
-        skynet_self_aware_time = datetime.datetime(1997, 8, 29, 6, 14, 0,
-                                                   tzinfo=iso8601.iso8601.UTC)
-        self.assertEqual(skynet_self_aware_time,
-                         timeutils.parse_isotime(skynet_self_aware_time_str))
+        expect = timeutils.parse_isotime(self.skynet_self_aware_time_str)
+        self.assertEqual(self.skynet_self_aware_time, expect)
+
+    def test_strtime(self):
+        expect = timeutils.strtime(self.skynet_self_aware_time_perfect)
+        self.assertEqual(self.skynet_self_aware_time_perfect_str, expect)
+
+    def test_parse_strtime(self):
+        perfect_time_format = self.skynet_self_aware_time_perfect_str
+        expect = timeutils.parse_strtime(perfect_time_format)
+        self.assertEqual(self.skynet_self_aware_time_perfect, expect)
+
+    def test_is_older_than(self):
+        with mock.patch('datetime.datetime') as datetime_mock:
+            datetime_mock.utcnow.return_value = self.skynet_self_aware_time
+            expect_true = timeutils.is_older_than(self.one_minute_before, 59)
+            self.assertTrue(expect_true)
+            expect_false = timeutils.is_older_than(self.one_minute_before, 60)
+            self.assertFalse(expect_false)
+            expect_false = timeutils.is_older_than(self.one_minute_before, 61)
+            self.assertFalse(expect_false)
+
+    def test_utcnow_ts(self):
+        skynet_self_aware_timestamp = 872806440.0
+        with mock.patch('datetime.datetime') as datetime_mock:
+            datetime_mock.utcnow.return_value = self.skynet_self_aware_time
+            ts = timeutils.utcnow_ts()
+            self.assertEqual(ts, skynet_self_aware_timestamp)
 
     def test_utcnow(self):
         timeutils.set_time_override(mock.sentinel.utcnow)
@@ -51,6 +85,16 @@ class TimeUtilsTest(unittest.TestCase):
 
         self.assertTrue(timeutils.utcnow())
 
+    def test_advance_time_delta(self):
+        timeutils.set_time_override(self.one_minute_before)
+        timeutils.advance_time_delta(datetime.timedelta(seconds=60))
+        self.assertEqual(timeutils.utcnow(), self.skynet_self_aware_time)
+
+    def test_advance_time_seconds(self):
+        timeutils.set_time_override(self.one_minute_before)
+        timeutils.advance_time_seconds(60)
+        self.assertEqual(timeutils.utcnow(), self.skynet_self_aware_time)
+
 
 class TestIso8601Time(unittest.TestCase):