From 4b184899062c70f5c673f2286e3b7a7c8fde6e76 Mon Sep 17 00:00:00 2001
From: Xie Yanbo <xieyanbo@gmail.com>
Date: Thu, 19 Mar 2020 18:09:21 +0800
Subject: [PATCH] A helpber to format datetime with local timezone

---
 coverage/backward.py | 26 ++++++++++++++++++++++++++
 coverage/html.py     |  4 ++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/coverage/backward.py b/coverage/backward.py
index 37b491676..92b0cf70a 100644
--- a/coverage/backward.py
+++ b/coverage/backward.py
@@ -9,6 +9,8 @@
 import os
 import sys
 
+from datetime import datetime
+
 from coverage import env
 
 
@@ -217,6 +219,30 @@ def __eq__(self, other):
             return self.__dict__ == other.__dict__
 
 
+def format_local_datetime(dt):
+    """Return a string with local timezone representing the date."""
+    try:
+        return dt.astimezone().strftime('%Y-%m-%d %H:%M %z')
+    except (TypeError, ValueError):
+        # Class datetime.timezone introduced in Python 3.2
+        # Datetime.astimezone in Python 3.5 can not handle naive datetime
+        import time
+        def get_timezone_offset():
+            timestamp = time.time()
+            delta = datetime.fromtimestamp(timestamp) - datetime.utcfromtimestamp(timestamp)
+            if delta.seconds >= 0:
+                sign = '+'
+                seconds = delta.seconds
+            else:
+                sign = '-'
+                seconds = - delta.seconds
+            hours, rest = divmod(seconds, 60 * 60)
+            minutes, _ = divmod(rest, 60)
+            return '%s%02d%02d' % (sign, hours, minutes)
+        offset = get_timezone_offset()
+        return '%s %s' % (dt.strftime('%Y-%m-%d %H:%M'), offset)
+
+
 def invalidate_import_caches():
     """Invalidate any import caches that may or may not exist."""
     if importlib and hasattr(importlib, "invalidate_caches"):
diff --git a/coverage/html.py b/coverage/html.py
index a8aa3f654..3596bbe1d 100644
--- a/coverage/html.py
+++ b/coverage/html.py
@@ -11,7 +11,7 @@
 
 import coverage
 from coverage import env
-from coverage.backward import iitems, SimpleNamespace
+from coverage.backward import iitems, SimpleNamespace, format_local_datetime
 from coverage.data import add_data_to_hash
 from coverage.files import flat_rootname
 from coverage.misc import CoverageException, ensure_dir, file_be_gone, Hasher, isolate_module
@@ -200,7 +200,7 @@ def __init__(self, cov):
             '__url__': coverage.__url__,
             '__version__': coverage.__version__,
             'title': title,
-            'time_stamp': datetime.datetime.now().astimezone().strftime('%Y-%m-%d %H:%M %z'),
+            'time_stamp': format_local_datetime(datetime.datetime.now()),
             'extra_css': self.extra_css,
             'has_arcs': self.has_arcs,
             'show_contexts': self.config.show_contexts,