Use timezone via settings to get PREFER_DATES_FROM result (#1155)

* tests(test_date_parser.py): add test when timezone is provided via settings

* fix(dateparser/parser.py): consider timezone provided via settings

* fix(dateparser/parser.py): fetch timezone details through inbuilt method

This ensures that we are still processing times such as EDT or AEDT which
returns UnknownTimezoneError with pytz.timezone method.

dateparser/parser.py

@@ -1,15 +1,15 @@
 import calendar
 import regex as re
 
+import pytz
 from io import StringIO
 from collections import OrderedDict
 from datetime import datetime
 from datetime import timedelta
-from pytz import utc
 
 from dateparser.utils import set_correct_day_from_settings, \
     get_last_day_of_month, get_previous_leap_year, get_next_leap_year, \
-    _get_missing_parts
+    _get_missing_parts, get_timezone_from_tz_string
 from dateparser.utils.strptime import strptime
 
 
@@ -460,7 +460,7 @@ def _correct_for_time_frame(self, dateobj, tz):
         # Since date comparisons must be either offset-naive or offset-aware, normalize dateobj
         # to be offset-aware if one or the other is already offset-aware.
         if self.now.tzinfo is not None and dateobj.tzinfo is None:
-            dateobj = utc.localize(dateobj)
+            dateobj = pytz.utc.localize(dateobj)
 
         if self.month and not self.year:
             try:
@@ -491,6 +491,11 @@ def _correct_for_time_frame(self, dateobj, tz):
                                          self._token_day,
                                          hasattr(self, '_token_weekday')]):
             # Convert dateobj to utc time to compare with self.now
+            try:
+                tz = tz or get_timezone_from_tz_string(self.settings.TIMEZONE)
+            except pytz.UnknownTimeZoneError:
+                tz = None
+
             if tz:
                 dateobj_time = (dateobj - tz.utcoffset(dateobj)).time()
             else:

tests/test_date_parser.py

@@ -869,27 +869,20 @@ def test_parsing_strings_containing_only_separator_tokens(self, date_string, exp
         self.then_date_obj_exactly_is(expected)
 
     @parameterized.expand([
-        param('4pm EDT', datetime(2021, 10, 19, 20, 0)),
+        param('4pm EDT', datetime(2021, 10, 19, 20, 0), {'PREFER_DATES_FROM': 'future'}),
+        param('11pm AEDT', datetime(2021, 10, 19, 12, 0), {'PREFER_DATES_FROM': 'past'}),
+        param('4pm', datetime(2021, 10, 19, 20, 0), {'PREFER_DATES_FROM': 'future', 'TIMEZONE': 'EDT'}),
+        param('11pm', datetime(2021, 10, 19, 12, 0), {'PREFER_DATES_FROM': 'past', 'TIMEZONE': 'AEDT'}),
     ])
-    def test_date_skip_ahead(self, date_string, expected):
-        self.given_parser(settings={'PREFER_DATES_FROM': 'future',
-                                    'TO_TIMEZONE': 'etc/utc',
-                                    'RETURN_AS_TIMEZONE_AWARE': False,
-                                    'RELATIVE_BASE': datetime(2021, 10, 19, 18, 0),
-                                    })
-        self.when_date_is_parsed(date_string)
-        self.then_date_was_parsed_by_date_parser()
-        self.then_date_obj_exactly_is(expected)
-
-    @parameterized.expand([
-        param('11pm AEDT', datetime(2021, 10, 19, 12, 0)),
-    ])
-    def test_date_step_back(self, date_string, expected):
-        self.given_parser(settings={'PREFER_DATES_FROM': 'past',
-                                    'TO_TIMEZONE': 'etc/utc',
-                                    'RETURN_AS_TIMEZONE_AWARE': False,
-                                    'RELATIVE_BASE': datetime(2021, 10, 19, 18, 0),
-                                    })
+    def test_prefer_dates_from_with_timezone(self, date_string, expected, test_settings):
+        self.given_parser(
+            settings={
+                'TO_TIMEZONE': 'etc/utc',
+                'RETURN_AS_TIMEZONE_AWARE': False,
+                'RELATIVE_BASE': datetime(2021, 10, 19, 18, 0),
+                **test_settings
+            }
+        )
         self.when_date_is_parsed(date_string)
         self.then_date_was_parsed_by_date_parser()
         self.then_date_obj_exactly_is(expected)