Fix bug for not existent or ambiguous datetime during native to aware conversion…

Fix bug for not existent or ambiguous datetime during native to aware conversion in timezone with DST.
Ref: #4986

rest_framework/fields.py

@@ -1085,6 +1085,7 @@ class DateTimeField(Field):
     default_error_messages = {
         'invalid': _('Datetime has wrong format. Use one of these formats instead: {format}.'),
         'date': _('Expected a datetime but got a date.'),
+        'make_aware': _('Datetime can not be represented in timezone "{timezone}".')
     }
     datetime_parser = datetime.datetime.strptime
 
@@ -1105,7 +1106,10 @@ class DateTimeField(Field):
         field_timezone = getattr(self, 'timezone', self.default_timezone())
 
         if (field_timezone is not None) and not timezone.is_aware(value):
+            try:
                 return timezone.make_aware(value, field_timezone)
+            except Exception:
+                self.fail('make_aware', timezone=field_timezone)
         elif (field_timezone is None) and timezone.is_aware(value):
             return timezone.make_naive(value, utc)
         return value

tests/test_fields.py

@@ -9,7 +9,7 @@ import pytest
 from django.http import QueryDict
 from django.test import TestCase, override_settings
 from django.utils import six
-from django.utils.timezone import utc, pytz
+from django.utils.timezone import pytz, utc
 
 import rest_framework
 from rest_framework import serializers
@@ -1213,10 +1213,8 @@ class TestNaiveDayLightSavingTimeTimeZoneDateTimeField(FieldValues):
     """
     valid_inputs = {}
     invalid_inputs = {
-        '2017-03-12T02:30:00': [
-            'Datetime can not be converted to server timezone due to NonExistentTimeError.'],
-        '2017-11-05T01:30:00': [
-            'Datetime can not be converted to server timezone due to AmbiguousTimeError.']
+        '2017-03-12T02:30:00': ['Datetime can not be represented in timezone "America/New_York".'],
+        '2017-11-05T01:30:00': ['Datetime can not be represented in timezone "America/New_York".']
     }
     outputs = {}
     field = serializers.DateTimeField(default_timezone=pytz.timezone('America/New_York'))