mirror of
https://github.com/encode/django-rest-framework.git
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Enable cursor pagination of value querysets. (#4569)
To do `GROUP_BY` queries in django requires one to use `.values()`
eg this groups posts by user getting a count of posts per user.
```
Posts.objects.order_by('user').values('user').annotate(post_count=Count('post'))
```
This would produce a value queryset which serializes its result
objects as dictionaries while `CursorPagination` requires a queryset
with result objects that are model instances.
This commit enables cursor pagination for value querysets.
- had to mangle the tests a bit to test it out. They might need
some refactoring.
- tried the same for `.values_list()` but it turned out to be
trickier than I expected since you have to use tuple indexes.
This commit is contained in:
Kennedy Mwenja
Tom Christie
parent
97d848413e
commit
7038571157
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@ -711,7 +711,11 @@ class CursorPagination(BasePagination):
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return replace_query_param(self.base_url, self.cursor_query_param, encoded)
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def _get_position_from_instance(self, instance, ordering):
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attr = getattr(instance, ordering[0].lstrip('-'))
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field_name = ordering[0].lstrip('-')
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if isinstance(instance, dict):
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attr = instance[field_name]
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else:
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attr = getattr(instance, field_name)
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return six.text_type(attr)
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def get_paginated_response(self, data):
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@ -3,6 +3,8 @@ from __future__ import unicode_literals
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import pytest
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from django.core.paginator import Paginator as DjangoPaginator
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from django.db import models
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from django.test import TestCase
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from rest_framework import (
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exceptions, filters, generics, pagination, serializers, status
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@ -530,85 +532,7 @@ class TestLimitOffset:
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assert content.get('previous') == prev_url
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class TestCursorPagination:
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"""
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Unit tests for `pagination.CursorPagination`.
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"""
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def setup(self):
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class MockObject(object):
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def __init__(self, idx):
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self.created = idx
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class MockQuerySet(object):
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def __init__(self, items):
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self.items = items
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def filter(self, created__gt=None, created__lt=None):
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if created__gt is not None:
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return MockQuerySet([
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item for item in self.items
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if item.created > int(created__gt)
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])
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assert created__lt is not None
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return MockQuerySet([
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item for item in self.items
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if item.created < int(created__lt)
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])
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def order_by(self, *ordering):
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if ordering[0].startswith('-'):
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return MockQuerySet(list(reversed(self.items)))
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return self
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def __getitem__(self, sliced):
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return self.items[sliced]
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class ExamplePagination(pagination.CursorPagination):
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page_size = 5
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ordering = 'created'
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self.pagination = ExamplePagination()
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self.queryset = MockQuerySet([
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MockObject(idx) for idx in [
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1, 1, 1, 1, 1,
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1, 2, 3, 4, 4,
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4, 4, 5, 6, 7,
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7, 7, 7, 7, 7,
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7, 7, 7, 8, 9,
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9, 9, 9, 9, 9
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]
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])
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def get_pages(self, url):
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"""
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Given a URL return a tuple of:
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(previous page, current page, next page, previous url, next url)
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"""
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request = Request(factory.get(url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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current = [item.created for item in queryset]
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next_url = self.pagination.get_next_link()
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previous_url = self.pagination.get_previous_link()
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if next_url is not None:
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request = Request(factory.get(next_url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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next = [item.created for item in queryset]
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else:
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next = None
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if previous_url is not None:
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request = Request(factory.get(previous_url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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previous = [item.created for item in queryset]
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else:
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previous = None
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return (previous, current, next, previous_url, next_url)
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class CursorPaginationTestsMixin:
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def test_invalid_cursor(self):
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request = Request(factory.get('/', {'cursor': '123'}))
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@ -703,6 +627,145 @@ class TestCursorPagination:
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assert isinstance(self.pagination.to_html(), type(''))
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class TestCursorPagination(CursorPaginationTestsMixin):
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"""
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Unit tests for `pagination.CursorPagination`.
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"""
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def setup(self):
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class MockObject(object):
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def __init__(self, idx):
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self.created = idx
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class MockQuerySet(object):
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def __init__(self, items):
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self.items = items
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def filter(self, created__gt=None, created__lt=None):
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if created__gt is not None:
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return MockQuerySet([
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item for item in self.items
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if item.created > int(created__gt)
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])
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assert created__lt is not None
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return MockQuerySet([
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item for item in self.items
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if item.created < int(created__lt)
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])
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def order_by(self, *ordering):
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if ordering[0].startswith('-'):
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return MockQuerySet(list(reversed(self.items)))
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return self
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def __getitem__(self, sliced):
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return self.items[sliced]
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class ExamplePagination(pagination.CursorPagination):
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page_size = 5
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ordering = 'created'
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self.pagination = ExamplePagination()
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self.queryset = MockQuerySet([
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MockObject(idx) for idx in [
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1, 1, 1, 1, 1,
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1, 2, 3, 4, 4,
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4, 4, 5, 6, 7,
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7, 7, 7, 7, 7,
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7, 7, 7, 8, 9,
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9, 9, 9, 9, 9
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]
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])
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def get_pages(self, url):
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"""
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Given a URL return a tuple of:
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(previous page, current page, next page, previous url, next url)
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"""
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request = Request(factory.get(url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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current = [item.created for item in queryset]
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next_url = self.pagination.get_next_link()
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previous_url = self.pagination.get_previous_link()
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if next_url is not None:
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request = Request(factory.get(next_url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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next = [item.created for item in queryset]
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else:
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next = None
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if previous_url is not None:
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request = Request(factory.get(previous_url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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previous = [item.created for item in queryset]
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else:
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previous = None
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return (previous, current, next, previous_url, next_url)
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class CursorPaginationModel(models.Model):
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created = models.IntegerField()
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class TestCursorPaginationWithValueQueryset(CursorPaginationTestsMixin, TestCase):
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"""
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Unit tests for `pagination.CursorPagination` for value querysets.
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"""
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def setUp(self):
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class ExamplePagination(pagination.CursorPagination):
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page_size = 5
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ordering = 'created'
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self.pagination = ExamplePagination()
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data = [
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1, 1, 1, 1, 1,
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1, 2, 3, 4, 4,
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4, 4, 5, 6, 7,
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7, 7, 7, 7, 7,
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7, 7, 7, 8, 9,
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9, 9, 9, 9, 9
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]
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for idx in data:
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CursorPaginationModel.objects.create(created=idx)
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self.queryset = CursorPaginationModel.objects.values()
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def get_pages(self, url):
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"""
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Given a URL return a tuple of:
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(previous page, current page, next page, previous url, next url)
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"""
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request = Request(factory.get(url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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current = [item['created'] for item in queryset]
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next_url = self.pagination.get_next_link()
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previous_url = self.pagination.get_previous_link()
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if next_url is not None:
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request = Request(factory.get(next_url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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next = [item['created'] for item in queryset]
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else:
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next = None
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if previous_url is not None:
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request = Request(factory.get(previous_url))
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queryset = self.pagination.paginate_queryset(self.queryset, request)
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previous = [item['created'] for item in queryset]
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else:
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previous = None
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return (previous, current, next, previous_url, next_url)
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def test_get_displayed_page_numbers():
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"""
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Test our contextual page display function.
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