[stable-2.10] facts - fix incorrect time for some date_time_facts (#70665) (#70996)

* [stable-2.10] facts - fix incorrect time for some date_time_facts (#70665)

The iso8601_micro and iso8601 facts incorrectly called now.utcnow(), resulting
in a new timestamp at the time it was called, not a conversion of the previously
stored timestamp.

Correct this by capturing the UTC timestamp once then calculating the local
time using the UTC offset of the current system.

* Use time.time() for getting the current time
* Convert from that stored epoch timestamp to local and UTC times
* Used existing timestamp for epoch time
* Add unit tests that validate the formate of the return value rather than an exact value since mocking time and timezone is non-trivial
(cherry picked from commit c4f442ed5a)

Co-authored-by: Sam Doran <sdoran@redhat.com>

* Remove tests for tz_dst since that only exists in newer versions

3 files changed, 113 insertions, 5 deletions

diff --git a/changelogs/fragments/date-time-facts-fix-utctime.yml b/changelogs/fragments/date-time-facts-fix-utctime.yml
new file mode 100644
index 0000000000..2a5bf8c408
--- /dev/null
+++ b/changelogs/fragments/date-time-facts-fix-utctime.yml
@@ -0,0 +1,2 @@
+bugfixes:
+  - facts - fix incorrect UTC timestamp in ``iso8601_micro`` and ``iso8601``
diff --git a/lib/ansible/module_utils/facts/system/date_time.py b/lib/ansible/module_utils/facts/system/date_time.py
index f4e59705ef..aa59d5bc1b 100644
--- a/lib/ansible/module_utils/facts/system/date_time.py
+++ b/lib/ansible/module_utils/facts/system/date_time.py
@@ -32,7 +32,11 @@ class DateTimeFactCollector(BaseFactCollector):
         facts_dict = {}
         date_time_facts = {}
 
-        now = datetime.datetime.now()
+        # Store the timestamp once, then get local and UTC versions from that
+        epoch_ts = time.time()
+        now = datetime.datetime.fromtimestamp(epoch_ts)
+        utcnow = datetime.datetime.utcfromtimestamp(epoch_ts)
+
         date_time_facts['year'] = now.strftime('%Y')
         date_time_facts['month'] = now.strftime('%m')
         date_time_facts['weekday'] = now.strftime('%A')
@@ -44,12 +48,11 @@ class DateTimeFactCollector(BaseFactCollector):
         date_time_facts['second'] = now.strftime('%S')
         date_time_facts['epoch'] = now.strftime('%s')
         if date_time_facts['epoch'] == '' or date_time_facts['epoch'][0] == '%':
-            # NOTE: in this case, the epoch wont match the rest of the date_time facts? ie, it's a few milliseconds later..? -akl
-            date_time_facts['epoch'] = str(int(time.time()))
+            date_time_facts['epoch'] = str(int(epoch_ts))
         date_time_facts['date'] = now.strftime('%Y-%m-%d')
         date_time_facts['time'] = now.strftime('%H:%M:%S')
-        date_time_facts['iso8601_micro'] = now.utcnow().strftime("%Y-%m-%dT%H:%M:%S.%fZ")
-        date_time_facts['iso8601'] = now.utcnow().strftime("%Y-%m-%dT%H:%M:%SZ")
+        date_time_facts['iso8601_micro'] = utcnow.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
+        date_time_facts['iso8601'] = utcnow.strftime("%Y-%m-%dT%H:%M:%SZ")
         date_time_facts['iso8601_basic'] = now.strftime("%Y%m%dT%H%M%S%f")
         date_time_facts['iso8601_basic_short'] = now.strftime("%Y%m%dT%H%M%S")
         date_time_facts['tz'] = time.strftime("%Z")
diff --git a/test/units/module_utils/facts/test_date_time.py b/test/units/module_utils/facts/test_date_time.py
new file mode 100644
index 0000000000..7c92e521db
--- /dev/null
+++ b/test/units/module_utils/facts/test_date_time.py
@@ -0,0 +1,103 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2020 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+import pytest
+import datetime
+import string
+import time
+
+from ansible.module_utils.facts.system import date_time
+
+EPOCH_TS = 1594449296.123456
+DT = datetime.datetime(2020, 7, 11, 12, 34, 56, 124356)
+DT_UTC = datetime.datetime(2020, 7, 11, 2, 34, 56, 124356)
+
+
+@pytest.fixture
+def fake_now(monkeypatch):
+    """
+    Patch `datetime.datetime.fromtimestamp()`, `datetime.datetime.utcfromtimestamp()`,
+    and `time.time()` to return deterministic values.
+    """
+
+    class FakeNow:
+        @classmethod
+        def fromtimestamp(cls, timestamp):
+            return DT
+
+        @classmethod
+        def utcfromtimestamp(cls, timestamp):
+            return DT_UTC
+
+    def _time():
+        return EPOCH_TS
+
+    monkeypatch.setattr(date_time.datetime, 'datetime', FakeNow)
+    monkeypatch.setattr(time, 'time', _time)
+
+
+@pytest.fixture
+def fake_date_facts(fake_now):
+    """Return a predictable instance of collected date_time facts."""
+
+    collector = date_time.DateTimeFactCollector()
+    data = collector.collect()
+
+    return data
+
+
+@pytest.mark.parametrize(
+    ('fact_name', 'fact_value'),
+    (
+        ('year', '2020'),
+        ('month', '07'),
+        ('weekday', 'Saturday'),
+        ('weekday_number', '6'),
+        ('weeknumber', '27'),
+        ('day', '11'),
+        ('hour', '12'),
+        ('minute', '34'),
+        ('second', '56'),
+        ('date', '2020-07-11'),
+        ('time', '12:34:56'),
+        ('iso8601_basic', '20200711T123456124356'),
+        ('iso8601_basic_short', '20200711T123456'),
+        ('iso8601_micro', '2020-07-11T02:34:56.124356Z'),
+        ('iso8601', '2020-07-11T02:34:56Z'),
+    ),
+)
+def test_date_time_facts(fake_date_facts, fact_name, fact_value):
+    assert fake_date_facts['date_time'][fact_name] == fact_value
+
+
+def test_date_time_epoch(fake_date_facts):
+    """Test that format of returned epoch value is correct"""
+
+    assert fake_date_facts['date_time']['epoch'].isdigit()
+    assert len(fake_date_facts['date_time']['epoch']) == 10  # This length will not change any time soon
+
+
+def test_date_time_tz(fake_date_facts):
+    """
+    Test that the returned value for timezone consists of only uppercase
+    letters and is the expected length.
+    """
+
+    assert fake_date_facts['date_time']['tz'].isupper()
+    assert 2 <= len(fake_date_facts['date_time']['tz']) <= 5
+    assert not set(fake_date_facts['date_time']['tz']).difference(set(string.ascii_uppercase))
+
+
+def test_date_time_tz_offset(fake_date_facts):
+    """
+    Test that the timezone offset begins with a `+` or `-` and ends with a
+    series of integers.
+    """
+
+    assert fake_date_facts['date_time']['tz_offset'][0] in ['-', '+']
+    assert fake_date_facts['date_time']['tz_offset'][1:].isdigit()
+    assert len(fake_date_facts['date_time']['tz_offset']) == 5