# from __future__ import unicode_literals
# from django.db import models
# from django.test import TestCase
# from django.utils import six
# from rest_framework import serializers
# from tests.models import (
#     BlogPost, ManyToManyTarget, ManyToManySource, ForeignKeyTarget, ForeignKeySource,
#     NullableForeignKeySource, OneToOneTarget, NullableOneToOneSource,
# )


# # ManyToMany
# class ManyToManyTargetSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = ManyToManyTarget
#         fields = ('id', 'name', 'sources')


# class ManyToManySourceSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = ManyToManySource
#         fields = ('id', 'name', 'targets')


# # ForeignKey
# class ForeignKeyTargetSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = ForeignKeyTarget
#         fields = ('id', 'name', 'sources')


# class ForeignKeySourceSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = ForeignKeySource
#         fields = ('id', 'name', 'target')


# # Nullable ForeignKey
# class NullableForeignKeySourceSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = NullableForeignKeySource
#         fields = ('id', 'name', 'target')


# # Nullable OneToOne
# class NullableOneToOneTargetSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = OneToOneTarget
#         fields = ('id', 'name', 'nullable_source')


# # TODO: Add test that .data cannot be accessed prior to .is_valid

# class PKManyToManyTests(TestCase):
#     def setUp(self):
#         for idx in range(1, 4):
#             target = ManyToManyTarget(name='target-%d' % idx)
#             target.save()
#             source = ManyToManySource(name='source-%d' % idx)
#             source.save()
#             for target in ManyToManyTarget.objects.all():
#                 source.targets.add(target)

#     def test_many_to_many_retrieve(self):
#         queryset = ManyToManySource.objects.all()
#         serializer = ManyToManySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'targets': [1]},
#             {'id': 2, 'name': 'source-2', 'targets': [1, 2]},
#             {'id': 3, 'name': 'source-3', 'targets': [1, 2, 3]}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_reverse_many_to_many_retrieve(self):
#         queryset = ManyToManyTarget.objects.all()
#         serializer = ManyToManyTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'sources': [1, 2, 3]},
#             {'id': 2, 'name': 'target-2', 'sources': [2, 3]},
#             {'id': 3, 'name': 'target-3', 'sources': [3]}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_many_to_many_update(self):
#         data = {'id': 1, 'name': 'source-1', 'targets': [1, 2, 3]}
#         instance = ManyToManySource.objects.get(pk=1)
#         serializer = ManyToManySourceSerializer(instance, data=data)
#         self.assertTrue(serializer.is_valid())
#         serializer.save()
#         self.assertEqual(serializer.data, data)

#         # Ensure source 1 is updated, and everything else is as expected
#         queryset = ManyToManySource.objects.all()
#         serializer = ManyToManySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'targets': [1, 2, 3]},
#             {'id': 2, 'name': 'source-2', 'targets': [1, 2]},
#             {'id': 3, 'name': 'source-3', 'targets': [1, 2, 3]}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_reverse_many_to_many_update(self):
#         data = {'id': 1, 'name': 'target-1', 'sources': [1]}
#         instance = ManyToManyTarget.objects.get(pk=1)
#         serializer = ManyToManyTargetSerializer(instance, data=data)
#         self.assertTrue(serializer.is_valid())
#         serializer.save()
#         self.assertEqual(serializer.data, data)

#         # Ensure target 1 is updated, and everything else is as expected
#         queryset = ManyToManyTarget.objects.all()
#         serializer = ManyToManyTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'sources': [1]},
#             {'id': 2, 'name': 'target-2', 'sources': [2, 3]},
#             {'id': 3, 'name': 'target-3', 'sources': [3]}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_many_to_many_create(self):
#         data = {'id': 4, 'name': 'source-4', 'targets': [1, 3]}
#         serializer = ManyToManySourceSerializer(data=data)
#         self.assertTrue(serializer.is_valid())
#         obj = serializer.save()
#         self.assertEqual(serializer.data, data)
#         self.assertEqual(obj.name, 'source-4')

#         # Ensure source 4 is added, and everything else is as expected
#         queryset = ManyToManySource.objects.all()
#         serializer = ManyToManySourceSerializer(queryset, many=True)
#         self.assertFalse(serializer.fields['targets'].read_only)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'targets': [1]},
#             {'id': 2, 'name': 'source-2', 'targets': [1, 2]},
#             {'id': 3, 'name': 'source-3', 'targets': [1, 2, 3]},
#             {'id': 4, 'name': 'source-4', 'targets': [1, 3]},
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_reverse_many_to_many_create(self):
#         data = {'id': 4, 'name': 'target-4', 'sources': [1, 3]}
#         serializer = ManyToManyTargetSerializer(data=data)
#         self.assertFalse(serializer.fields['sources'].read_only)
#         self.assertTrue(serializer.is_valid())
#         obj = serializer.save()
#         self.assertEqual(serializer.data, data)
#         self.assertEqual(obj.name, 'target-4')

#         # Ensure target 4 is added, and everything else is as expected
#         queryset = ManyToManyTarget.objects.all()
#         serializer = ManyToManyTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'sources': [1, 2, 3]},
#             {'id': 2, 'name': 'target-2', 'sources': [2, 3]},
#             {'id': 3, 'name': 'target-3', 'sources': [3]},
#             {'id': 4, 'name': 'target-4', 'sources': [1, 3]}
#         ]
#         self.assertEqual(serializer.data, expected)


# class PKForeignKeyTests(TestCase):
#     def setUp(self):
#         target = ForeignKeyTarget(name='target-1')
#         target.save()
#         new_target = ForeignKeyTarget(name='target-2')
#         new_target.save()
#         for idx in range(1, 4):
#             source = ForeignKeySource(name='source-%d' % idx, target=target)
#             source.save()

#     def test_foreign_key_retrieve(self):
#         queryset = ForeignKeySource.objects.all()
#         serializer = ForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': 1},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': 1}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_reverse_foreign_key_retrieve(self):
#         queryset = ForeignKeyTarget.objects.all()
#         serializer = ForeignKeyTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'sources': [1, 2, 3]},
#             {'id': 2, 'name': 'target-2', 'sources': []},
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_update(self):
#         data = {'id': 1, 'name': 'source-1', 'target': 2}
#         instance = ForeignKeySource.objects.get(pk=1)
#         serializer = ForeignKeySourceSerializer(instance, data=data)
#         self.assertTrue(serializer.is_valid())
#         self.assertEqual(serializer.data, data)
#         serializer.save()

#         # Ensure source 1 is updated, and everything else is as expected
#         queryset = ForeignKeySource.objects.all()
#         serializer = ForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': 2},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': 1}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_update_incorrect_type(self):
#         data = {'id': 1, 'name': 'source-1', 'target': 'foo'}
#         instance = ForeignKeySource.objects.get(pk=1)
#         serializer = ForeignKeySourceSerializer(instance, data=data)
#         self.assertFalse(serializer.is_valid())
#         self.assertEqual(serializer.errors, {'target': ['Incorrect type.  Expected pk value, received %s.' % six.text_type.__name__]})

#     def test_reverse_foreign_key_update(self):
#         data = {'id': 2, 'name': 'target-2', 'sources': [1, 3]}
#         instance = ForeignKeyTarget.objects.get(pk=2)
#         serializer = ForeignKeyTargetSerializer(instance, data=data)
#         self.assertTrue(serializer.is_valid())
#         # We shouldn't have saved anything to the db yet since save
#         # hasn't been called.
#         queryset = ForeignKeyTarget.objects.all()
#         new_serializer = ForeignKeyTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'sources': [1, 2, 3]},
#             {'id': 2, 'name': 'target-2', 'sources': []},
#         ]
#         self.assertEqual(new_serializer.data, expected)

#         serializer.save()
#         self.assertEqual(serializer.data, data)

#         # Ensure target 2 is update, and everything else is as expected
#         queryset = ForeignKeyTarget.objects.all()
#         serializer = ForeignKeyTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'sources': [2]},
#             {'id': 2, 'name': 'target-2', 'sources': [1, 3]},
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_create(self):
#         data = {'id': 4, 'name': 'source-4', 'target': 2}
#         serializer = ForeignKeySourceSerializer(data=data)
#         self.assertTrue(serializer.is_valid())
#         obj = serializer.save()
#         self.assertEqual(serializer.data, data)
#         self.assertEqual(obj.name, 'source-4')

#         # Ensure source 4 is added, and everything else is as expected
#         queryset = ForeignKeySource.objects.all()
#         serializer = ForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': 1},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': 1},
#             {'id': 4, 'name': 'source-4', 'target': 2},
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_reverse_foreign_key_create(self):
#         data = {'id': 3, 'name': 'target-3', 'sources': [1, 3]}
#         serializer = ForeignKeyTargetSerializer(data=data)
#         self.assertTrue(serializer.is_valid())
#         obj = serializer.save()
#         self.assertEqual(serializer.data, data)
#         self.assertEqual(obj.name, 'target-3')

#         # Ensure target 3 is added, and everything else is as expected
#         queryset = ForeignKeyTarget.objects.all()
#         serializer = ForeignKeyTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'sources': [2]},
#             {'id': 2, 'name': 'target-2', 'sources': []},
#             {'id': 3, 'name': 'target-3', 'sources': [1, 3]},
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_update_with_invalid_null(self):
#         data = {'id': 1, 'name': 'source-1', 'target': None}
#         instance = ForeignKeySource.objects.get(pk=1)
#         serializer = ForeignKeySourceSerializer(instance, data=data)
#         self.assertFalse(serializer.is_valid())
#         self.assertEqual(serializer.errors, {'target': ['This field is required.']})

#     def test_foreign_key_with_empty(self):
#         """
#         Regression test for #1072

#         https://github.com/tomchristie/django-rest-framework/issues/1072
#         """
#         serializer = NullableForeignKeySourceSerializer()
#         self.assertEqual(serializer.data['target'], None)


# class PKNullableForeignKeyTests(TestCase):
#     def setUp(self):
#         target = ForeignKeyTarget(name='target-1')
#         target.save()
#         for idx in range(1, 4):
#             if idx == 3:
#                 target = None
#             source = NullableForeignKeySource(name='source-%d' % idx, target=target)
#             source.save()

#     def test_foreign_key_retrieve_with_null(self):
#         queryset = NullableForeignKeySource.objects.all()
#         serializer = NullableForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': 1},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': None},
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_create_with_valid_null(self):
#         data = {'id': 4, 'name': 'source-4', 'target': None}
#         serializer = NullableForeignKeySourceSerializer(data=data)
#         self.assertTrue(serializer.is_valid())
#         obj = serializer.save()
#         self.assertEqual(serializer.data, data)
#         self.assertEqual(obj.name, 'source-4')

#         # Ensure source 4 is created, and everything else is as expected
#         queryset = NullableForeignKeySource.objects.all()
#         serializer = NullableForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': 1},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': None},
#             {'id': 4, 'name': 'source-4', 'target': None}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_create_with_valid_emptystring(self):
#         """
#         The emptystring should be interpreted as null in the context
#         of relationships.
#         """
#         data = {'id': 4, 'name': 'source-4', 'target': ''}
#         expected_data = {'id': 4, 'name': 'source-4', 'target': None}
#         serializer = NullableForeignKeySourceSerializer(data=data)
#         self.assertTrue(serializer.is_valid())
#         obj = serializer.save()
#         self.assertEqual(serializer.data, expected_data)
#         self.assertEqual(obj.name, 'source-4')

#         # Ensure source 4 is created, and everything else is as expected
#         queryset = NullableForeignKeySource.objects.all()
#         serializer = NullableForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': 1},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': None},
#             {'id': 4, 'name': 'source-4', 'target': None}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_update_with_valid_null(self):
#         data = {'id': 1, 'name': 'source-1', 'target': None}
#         instance = NullableForeignKeySource.objects.get(pk=1)
#         serializer = NullableForeignKeySourceSerializer(instance, data=data)
#         self.assertTrue(serializer.is_valid())
#         self.assertEqual(serializer.data, data)
#         serializer.save()

#         # Ensure source 1 is updated, and everything else is as expected
#         queryset = NullableForeignKeySource.objects.all()
#         serializer = NullableForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': None},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': None}
#         ]
#         self.assertEqual(serializer.data, expected)

#     def test_foreign_key_update_with_valid_emptystring(self):
#         """
#         The emptystring should be interpreted as null in the context
#         of relationships.
#         """
#         data = {'id': 1, 'name': 'source-1', 'target': ''}
#         expected_data = {'id': 1, 'name': 'source-1', 'target': None}
#         instance = NullableForeignKeySource.objects.get(pk=1)
#         serializer = NullableForeignKeySourceSerializer(instance, data=data)
#         self.assertTrue(serializer.is_valid())
#         self.assertEqual(serializer.data, expected_data)
#         serializer.save()

#         # Ensure source 1 is updated, and everything else is as expected
#         queryset = NullableForeignKeySource.objects.all()
#         serializer = NullableForeignKeySourceSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'source-1', 'target': None},
#             {'id': 2, 'name': 'source-2', 'target': 1},
#             {'id': 3, 'name': 'source-3', 'target': None}
#         ]
#         self.assertEqual(serializer.data, expected)

#     # reverse foreign keys MUST be read_only
#     # In the general case they do not provide .remove() or .clear()
#     # and cannot be arbitrarily set.

#     # def test_reverse_foreign_key_update(self):
#     #     data = {'id': 1, 'name': 'target-1', 'sources': [1]}
#     #     instance = ForeignKeyTarget.objects.get(pk=1)
#     #     serializer = ForeignKeyTargetSerializer(instance, data=data)
#     #     self.assertTrue(serializer.is_valid())
#     #     self.assertEqual(serializer.data, data)
#     #     serializer.save()

#     #     # Ensure target 1 is updated, and everything else is as expected
#     #     queryset = ForeignKeyTarget.objects.all()
#     #     serializer = ForeignKeyTargetSerializer(queryset, many=True)
#     #     expected = [
#     #         {'id': 1, 'name': 'target-1', 'sources': [1]},
#     #         {'id': 2, 'name': 'target-2', 'sources': []},
#     #     ]
#     #     self.assertEqual(serializer.data, expected)


# class PKNullableOneToOneTests(TestCase):
#     def setUp(self):
#         target = OneToOneTarget(name='target-1')
#         target.save()
#         new_target = OneToOneTarget(name='target-2')
#         new_target.save()
#         source = NullableOneToOneSource(name='source-1', target=new_target)
#         source.save()

#     def test_reverse_foreign_key_retrieve_with_null(self):
#         queryset = OneToOneTarget.objects.all()
#         serializer = NullableOneToOneTargetSerializer(queryset, many=True)
#         expected = [
#             {'id': 1, 'name': 'target-1', 'nullable_source': None},
#             {'id': 2, 'name': 'target-2', 'nullable_source': 1},
#         ]
#         self.assertEqual(serializer.data, expected)


# # The below models and tests ensure that serializer fields corresponding
# # to a ManyToManyField field with a user-specified ``through`` model are
# # set to read only


# class ManyToManyThroughTarget(models.Model):
#     name = models.CharField(max_length=100)


# class ManyToManyThrough(models.Model):
#     source = models.ForeignKey('ManyToManyThroughSource')
#     target = models.ForeignKey(ManyToManyThroughTarget)


# class ManyToManyThroughSource(models.Model):
#     name = models.CharField(max_length=100)
#     targets = models.ManyToManyField(ManyToManyThroughTarget,
#                                      related_name='sources',
#                                      through='ManyToManyThrough')


# class ManyToManyThroughTargetSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = ManyToManyThroughTarget
#         fields = ('id', 'name', 'sources')


# class ManyToManyThroughSourceSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = ManyToManyThroughSource
#         fields = ('id', 'name', 'targets')


# class PKManyToManyThroughTests(TestCase):
#     def setUp(self):
#         self.source = ManyToManyThroughSource.objects.create(
#             name='through-source-1')
#         self.target = ManyToManyThroughTarget.objects.create(
#             name='through-target-1')

#     def test_many_to_many_create(self):
#         data = {'id': 2, 'name': 'source-2', 'targets': [self.target.pk]}
#         serializer = ManyToManyThroughSourceSerializer(data=data)
#         self.assertTrue(serializer.fields['targets'].read_only)
#         self.assertTrue(serializer.is_valid())
#         obj = serializer.save()
#         self.assertEqual(obj.name, 'source-2')
#         self.assertEqual(obj.targets.count(), 0)

#     def test_many_to_many_reverse_create(self):
#         data = {'id': 2, 'name': 'target-2', 'sources': [self.source.pk]}
#         serializer = ManyToManyThroughTargetSerializer(data=data)
#         self.assertTrue(serializer.fields['sources'].read_only)
#         self.assertTrue(serializer.is_valid())
#         serializer.save()
#         obj = serializer.save()
#         self.assertEqual(obj.name, 'target-2')
#         self.assertEqual(obj.sources.count(), 0)


# # Regression tests for #694 (`source` attribute on related fields)


# class PrimaryKeyRelatedFieldSourceTests(TestCase):
#     def test_related_manager_source(self):
#         """
#         Relational fields should be able to use manager-returning methods as their source.
#         """
#         BlogPost.objects.create(title='blah')
#         field = serializers.PrimaryKeyRelatedField(many=True, source='get_blogposts_manager')

#         class ClassWithManagerMethod(object):
#             def get_blogposts_manager(self):
#                 return BlogPost.objects

#         obj = ClassWithManagerMethod()
#         value = field.field_to_native(obj, 'field_name')
#         self.assertEqual(value, [1])

#     def test_related_queryset_source(self):
#         """
#         Relational fields should be able to use queryset-returning methods as their source.
#         """
#         BlogPost.objects.create(title='blah')
#         field = serializers.PrimaryKeyRelatedField(many=True, source='get_blogposts_queryset')

#         class ClassWithQuerysetMethod(object):
#             def get_blogposts_queryset(self):
#                 return BlogPost.objects.all()

#         obj = ClassWithQuerysetMethod()
#         value = field.field_to_native(obj, 'field_name')
#         self.assertEqual(value, [1])

#     def test_dotted_source(self):
#         """
#         Source argument should support dotted.source notation.
#         """
#         BlogPost.objects.create(title='blah')
#         field = serializers.PrimaryKeyRelatedField(many=True, source='a.b.c')

#         class ClassWithQuerysetMethod(object):
#             a = {
#                 'b': {
#                     'c': BlogPost.objects.all()
#                 }
#             }

#         obj = ClassWithQuerysetMethod()
#         value = field.field_to_native(obj, 'field_name')
#         self.assertEqual(value, [1])
