def test_queryset_where_clauses(self):
        queryset = CursorQueryset(model=ExampleModel).all()

        cursor1 = queryset[:self.PAGE_SIZE].cursor()
        queryset1 = queryset.from_cursor(cursor1)

        cursor2 = queryset1[self.PAGE_SIZE:2 * self.PAGE_SIZE].cursor()
        queryset2 = queryset.from_cursor(cursor2)

        self.assertEqual(
            len(queryset1.query.where.children),
            len(queryset2.query.where.children),
            "Cursor generated querysets had different where clause lengths"
        )
    def test_queryset_consistent_with_data_insert(self):
        """
        Ensures that a cursor returned from a queryset stays fixed when new
        items are inserted.
        """
        queryset = CursorQueryset(model=ExampleModel).order_by('count_field')
        cursor = queryset[:self.PAGE_SIZE].cursor()

        assert cursor.token

        expected = set([
            x.pk for x in queryset[:self.PAGE_SIZE]
        ])

        first = queryset[0]

        # Now add some instances that would change the indexing
        for i in range(10):
            ExampleModelFactory.create(count_field=first.count_field - 1)

        queryset2 = queryset.from_cursor(cursor)

        actual = set([x.pk for x in queryset2[:self.PAGE_SIZE]])

        self.assertSetEqual(expected, actual)