fix: DateTimeWidget not timezone sensitive (#813) (#943)

BREAKING CHANGE: previously datetime fields where not exported in
regards to default timezone

fixes: #942, #813

import_export/widgets.py

@@ -192,6 +192,8 @@ class DateTimeWidget(Widget):
     def render(self, value, obj=None):
         if not value:
             return ""
+        if settings.USE_TZ:
+            value = timezone.localtime(value)
         return value.strftime(self.formats[0])
 
 

tests/core/admin.py

@@ -21,6 +21,7 @@ class BookResource(ModelResource):
 
 
 class BookAdmin(ImportExportMixin, admin.ModelAdmin):
+    list_display = ('name', 'author', 'added')
     list_filter = ['categories', 'author']
     resource_class = BookResource
 

tests/core/migrations/0008_auto_20190409_0846.py

@@ -0,0 +1,28 @@
+# Generated by Django 2.1.5 on 2019-04-09 06:46
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0007_auto_20180628_0411'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='EBook',
+            fields=[
+            ],
+            options={
+                'proxy': True,
+                'indexes': [],
+            },
+            bases=('core.book',),
+        ),
+        migrations.AddField(
+            model_name='book',
+            name='added',
+            field=models.DateTimeField(blank=True, null=True),
+        ),
+    ]

tests/core/models.py

@@ -40,6 +40,7 @@ class Book(models.Model):
     published = models.DateField('Published', blank=True, null=True)
     published_time = models.TimeField('Time published', blank=True, null=True)
     price = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True)
+    added = models.DateTimeField(blank=True, null=True)
 
     categories = models.ManyToManyField(Category, blank=True)
 

tests/core/tests/test_resources.py

@@ -291,6 +291,7 @@ class ModelResourceTest(TestCase):
         headers = self.resource.get_export_headers()
         self.assertEqual(headers, ['published_date', 'id', 'name', 'author',
                                    'author_email', 'published_time', 'price',
+                                   'added',
                                    'categories', ])
 
     def test_export(self):

tests/core/tests/test_widgets.py

@@ -1,6 +1,7 @@
 from datetime import date, datetime, time, timedelta
 from decimal import Decimal
 
+import pytz
 from core.models import Author, Category
 
 from django.test import TestCase
@@ -62,14 +63,11 @@ class DateTimeWidgetTest(TestCase):
         self.assertEqual(self.widget.clean("13.08.2012 18:00:00"),
                          self.datetime)
 
-    @override_settings(USE_TZ=True)
+    @override_settings(USE_TZ=True, TIME_ZONE='Europe/Ljubljana')
     def test_use_tz(self):
-        self.assertEqual(self.widget.render(self.datetime),
-                         "13.08.2012 18:00:00")
-        aware_dt = timezone.make_aware(self.datetime,
-                                       timezone.get_default_timezone())
-        self.assertEqual(self.widget.clean("13.08.2012 18:00:00"),
-                         aware_dt)
+        utc_dt = timezone.make_aware(self.datetime, pytz.UTC)
+        self.assertEqual(self.widget.render(utc_dt), "13.08.2012 20:00:00")
+        self.assertEqual(self.widget.clean("13.08.2012 20:00:00"), utc_dt)
 
 
 class DateWidgetBefore1900Test(TestCase):
@@ -289,4 +287,4 @@ class JSONWidgetTest(TestCase):
     def test_render_none(self):
         self.assertEqual(self.widget.render(None), None)
         self.assertEqual(self.widget.render(dict()), None)
-        self.assertEqual(self.widget.render({"value": None}), '{"value": null}')
+        self.assertEqual(self.widget.render({"value": None}), '{"value": null}')

tests/settings.py

@@ -100,3 +100,7 @@ LOGGING = {
     'root': {
         'handlers': ['console'],
     }}
+
+
+# USE_TZ = True
+# TIME_ZONE = 'Europe/Ljubljana'