Add test for timezone handling

test_ago.py

@@ -1,7 +1,6 @@
 from __future__ import print_function
 
-from datetime import datetime
-from datetime import timedelta
+from datetime import datetime, timedelta, tzinfo
 
 from ago import human
 from ago import delta2dict
@@ -17,6 +16,25 @@ FUTURE_DELTA = PRESENT - FUTURE
 ONE_YEAR_FOUR_HOURS_DELTA = timedelta(365, 14400, 0)
 
 
+class FixedOffset(tzinfo):
+    """Fixed offset in minutes east from UTC.
+
+    Adapted from Python's documentation about tzinfo objects:
+    https://docs.python.org/2.7/library/datetime.html#tzinfo-objects
+    """
+    def __init__(self, offset):
+        self._offset = timedelta(minutes=offset)
+
+    def utcoffset(self, dt):
+        return self._offset
+
+    def tzname(self, dt):
+        return "Test"
+
+    def dst(self, dt):
+        return timedelta(0)
+
+
 def test_human_passed_datetime_is_string():
     assert isinstance(human(PAST), str)
 
@@ -125,6 +143,19 @@ def test_valid_future_dict():
     assert past_dict["microsecond"] == 742
 
 
+def test_timezone_support():
+    # test a naive datetime with no timezone
+    # (add an extra minute to ensure it stays over an hour ahead during test)
+    dt = datetime.now() + timedelta(minutes=61)
+    output = human(dt)
+    assert output.startswith("in 1 hour")
+
+    # test a timezone-aware datetime with a UTC-2 timezone
+    dt = datetime.now(tz=FixedOffset(-120)) + timedelta(minutes=61)
+    output = human(dt)
+    assert output.startswith("in 1 hour")
+
+
 def example_usage():
     """Test and example usage"""